diff --git a/eth2/types/src/beacon_state.rs b/eth2/types/src/beacon_state.rs
index 1fc29f8e4..42022c89f 100644
--- a/eth2/types/src/beacon_state.rs
+++ b/eth2/types/src/beacon_state.rs
@@ -13,7 +13,7 @@ use test_random_derive::TestRandom;
 use tree_hash::TreeHash;
 use tree_hash_derive::{CachedTreeHash, TreeHash};
 
-pub use beacon_state_types::{BeaconStateTypes, FewValidatorsBeaconState, FoundationBeaconState};
+pub use beacon_state_types::*;
 
 pub mod beacon_state_types;
 mod epoch_cache;
diff --git a/eth2/types/src/beacon_state/beacon_state_types.rs b/eth2/types/src/beacon_state/beacon_state_types.rs
index 41f9f44c8..a77b4d4f1 100644
--- a/eth2/types/src/beacon_state/beacon_state_types.rs
+++ b/eth2/types/src/beacon_state/beacon_state_types.rs
@@ -7,30 +7,40 @@ pub trait BeaconStateTypes {
     type LatestRandaoMixesLength: Unsigned + Clone + Sync + Send;
     type LatestActiveIndexRootsLength: Unsigned + Clone + Sync + Send;
     type LatestSlashedExitLength: Unsigned + Clone + Sync + Send;
+
+    fn spec() -> ChainSpec;
 }
 
 #[derive(Clone, PartialEq, Debug)]
-pub struct FoundationStateParams;
+pub struct FoundationStateTypes;
 
-impl BeaconStateTypes for FoundationStateParams {
+impl BeaconStateTypes for FoundationStateTypes {
     type ShardCount = U1024;
     type SlotsPerHistoricalRoot = U8192;
     type LatestRandaoMixesLength = U8192;
     type LatestActiveIndexRootsLength = U8192;
     type LatestSlashedExitLength = U8192;
+
+    fn spec() -> ChainSpec {
+        ChainSpec::foundation()
+    }
 }
 
-pub type FoundationBeaconState = BeaconState<FoundationStateParams>;
+pub type FoundationBeaconState = BeaconState<FoundationStateTypes>;
 
 #[derive(Clone, PartialEq, Debug)]
-pub struct FewValidatorsStateParams;
+pub struct FewValidatorsStateTypes;
 
-impl BeaconStateTypes for FewValidatorsStateParams {
+impl BeaconStateTypes for FewValidatorsStateTypes {
     type ShardCount = U8;
     type SlotsPerHistoricalRoot = U8192;
     type LatestRandaoMixesLength = U8192;
     type LatestActiveIndexRootsLength = U8192;
     type LatestSlashedExitLength = U8192;
+
+    fn spec() -> ChainSpec {
+        ChainSpec::few_validators()
+    }
 }
 
-pub type FewValidatorsBeaconState = BeaconState<FewValidatorsStateParams>;
+pub type FewValidatorsBeaconState = BeaconState<FewValidatorsStateTypes>;
diff --git a/eth2/types/src/beacon_state/epoch_cache/tests.rs b/eth2/types/src/beacon_state/epoch_cache/tests.rs
index 182817bf6..6ba7c9086 100644
--- a/eth2/types/src/beacon_state/epoch_cache/tests.rs
+++ b/eth2/types/src/beacon_state/epoch_cache/tests.rs
@@ -1,7 +1,7 @@
 #![cfg(test)]
 
 use super::*;
-use crate::beacon_state::FewValidatorsBeaconState;
+use crate::beacon_state::FewValidatorsStateTypes;
 use crate::test_utils::*;
 use swap_or_not_shuffle::shuffle_list;
 
@@ -102,10 +102,13 @@ fn setup_sane_cache_test<T: BeaconStateTypes>(
 
 #[test]
 fn builds_sane_current_epoch_cache() {
-    let mut spec = ChainSpec::few_validators();
+    let mut spec = FewValidatorsStateTypes::spec();
     spec.shard_count = 4;
     let validator_count = (spec.shard_count * spec.target_committee_size) + 1;
-    let state: FewValidatorsBeaconState = setup_sane_cache_test(validator_count as usize, &spec);
+
+    let state: BeaconState<FewValidatorsStateTypes> =
+        setup_sane_cache_test(validator_count as usize, &spec);
+
     do_sane_cache_test(
         state.clone(),
         state.current_epoch(&spec),
@@ -119,10 +122,13 @@ fn builds_sane_current_epoch_cache() {
 
 #[test]
 fn builds_sane_previous_epoch_cache() {
-    let mut spec = ChainSpec::few_validators();
+    let mut spec = FewValidatorsStateTypes::spec();
     spec.shard_count = 2;
     let validator_count = (spec.shard_count * spec.target_committee_size) + 1;
-    let state: FewValidatorsBeaconState = setup_sane_cache_test(validator_count as usize, &spec);
+
+    let state: BeaconState<FewValidatorsStateTypes> =
+        setup_sane_cache_test(validator_count as usize, &spec);
+
     do_sane_cache_test(
         state.clone(),
         state.previous_epoch(&spec),
@@ -136,11 +142,13 @@ fn builds_sane_previous_epoch_cache() {
 
 #[test]
 fn builds_sane_next_without_update_epoch_cache() {
-    let mut spec = ChainSpec::few_validators();
+    let mut spec = FewValidatorsStateTypes::spec();
     spec.shard_count = 2;
     let validator_count = (spec.shard_count * spec.target_committee_size) + 1;
-    let mut state: FewValidatorsBeaconState =
+
+    let mut state: BeaconState<FewValidatorsStateTypes> =
         setup_sane_cache_test(validator_count as usize, &spec);
+
     state.validator_registry_update_epoch = state.slot.epoch(spec.slots_per_epoch);
     do_sane_cache_test(
         state.clone(),
diff --git a/eth2/types/src/beacon_state/tests.rs b/eth2/types/src/beacon_state/tests.rs
index b840663f0..8948a94f6 100644
--- a/eth2/types/src/beacon_state/tests.rs
+++ b/eth2/types/src/beacon_state/tests.rs
@@ -1,6 +1,6 @@
 #![cfg(test)]
 use super::*;
-use crate::beacon_state::{FewValidatorsBeaconState, FoundationBeaconState};
+use crate::beacon_state::FewValidatorsStateTypes;
 use crate::test_utils::*;
 
 ssz_tests!(FoundationBeaconState);
@@ -46,9 +46,11 @@ fn test_cache_initialization<'a, T: BeaconStateTypes>(
 
 #[test]
 fn cache_initialization() {
-    let spec = ChainSpec::few_validators();
-    let (mut state, _keypairs): (FewValidatorsBeaconState, Vec<Keypair>) =
-        TestingBeaconStateBuilder::from_default_keypairs_file_if_exists(16, &spec).build();
+    let spec = FewValidatorsStateTypes::spec();
+
+    let builder: TestingBeaconStateBuilder<FewValidatorsStateTypes> =
+        TestingBeaconStateBuilder::from_default_keypairs_file_if_exists(16, &spec);
+    let (mut state, _keypairs) = builder.build();
 
     state.slot = (spec.genesis_epoch + 1).start_slot(spec.slots_per_epoch);
 
diff --git a/eth2/types/src/chain_spec.rs b/eth2/types/src/chain_spec.rs
index 32f36a64d..974bcfc4a 100644
--- a/eth2/types/src/chain_spec.rs
+++ b/eth2/types/src/chain_spec.rs
@@ -154,7 +154,7 @@ impl ChainSpec {
     /// Returns a `ChainSpec` compatible with the Ethereum Foundation specification.
     ///
     /// Spec v0.5.1
-    pub fn foundation() -> Self {
+    pub(crate) fn foundation() -> Self {
         let genesis_slot = Slot::new(2_u64.pow(32));
         let slots_per_epoch = 64;
         let genesis_epoch = genesis_slot.epoch(slots_per_epoch);
@@ -248,7 +248,7 @@ impl ChainSpec {
     /// Returns a `ChainSpec` compatible with the Lighthouse testnet specification.
     ///
     /// Spec v0.4.0
-    pub fn lighthouse_testnet() -> Self {
+    pub(crate) fn lighthouse_testnet() -> Self {
         /*
          * Lighthouse testnet bootnodes
          */
@@ -264,7 +264,7 @@ impl ChainSpec {
     }
 
     /// Returns a `ChainSpec` compatible with the specification suitable for 8 validators.
-    pub fn few_validators() -> Self {
+    pub(crate) fn few_validators() -> Self {
         let genesis_slot = Slot::new(2_u64.pow(32));
         let slots_per_epoch = 8;
         let genesis_epoch = genesis_slot.epoch(slots_per_epoch);
diff --git a/eth2/types/src/historical_batch.rs b/eth2/types/src/historical_batch.rs
index fef6e2715..f9886b8c8 100644
--- a/eth2/types/src/historical_batch.rs
+++ b/eth2/types/src/historical_batch.rs
@@ -31,9 +31,9 @@ pub struct HistoricalBatch<T: BeaconStateTypes> {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::beacon_state::beacon_state_types::FoundationStateParams;
+    use crate::beacon_state::beacon_state_types::FoundationStateTypes;
 
-    pub type FoundationHistoricalBatch = HistoricalBatch<FoundationStateParams>;
+    pub type FoundationHistoricalBatch = HistoricalBatch<FoundationStateTypes>;
 
     ssz_tests!(FoundationHistoricalBatch);
     cached_tree_hash_tests!(FoundationHistoricalBatch);