diff --git a/piker/brokers/deribit/venues.py b/piker/brokers/deribit/venues.py
index 33d3139c..b814a068 100644
--- a/piker/brokers/deribit/venues.py
+++ b/piker/brokers/deribit/venues.py
@@ -64,19 +64,19 @@ class Pair(Struct, frozen=True, kw_only=True):
     quote_currency: str # 'BTC'
 
     # dst
-    settlement_currency: str # "BTC",
+    base_currency: str # "BTC",
 
     tick_size: float # 0.0001
     tick_size_steps: list[dict[str, str | int | float]] # [{'above_price': 0.005, 'tick_size': 0.0005}]
 
     @property
     def price_tick(self) -> Decimal:
-        step_size: str = self.tick_size_steps[0].get('above_price')
+        step_size: float = self.tick_size_steps[0].get('above_price')
         return Decimal(step_size)
 
     @property
     def size_tick(self) -> Decimal:
-        step_size: str = self.tick_size_steps[0].get('tick_size')
+        step_size: float = self.tick_size_steps[0].get('tick_size')
         return Decimal(step_size)
 
     @property
@@ -88,11 +88,12 @@ class Pair(Struct, frozen=True, kw_only=True):
         return f'{self.symbol}.{self.venue}'
 
 
-class OptionPair(Struct, frozen=True, kw_only=True):
+class OptionPair(Pair, frozen=True, kw_only=True):
 
     taker_commission: float # 0.0003
     strike: float # 5000.0
     settlement_period: str # 'day'
+    settlement_currency: str # "BTC",
     rfq: bool # false
     price_index: str # 'btc_usd'
     option_type: str # 'call'
@@ -129,7 +130,7 @@ class OptionPair(Struct, frozen=True, kw_only=True):
 
     @property
     def bs_dst_asset(self) -> str:
-        return f'{self.settlement_currency}'
+        return f'{self.base_currency}'
     
     @property
     def bs_mktid(self) -> str: