Black Brant ll Fin Unit BT50 for 18mm motors

Okay, you may think its a bit pricey but in fact its one of the more minimal designs with a minimum of material. It has more surface area due to its broad fins, but they are hollow to offset material costs for their sizable chord thickness. Again, it has centering rings and as with all my other fin cans, I recommend providing additional engine mount support with a longer engine tube/ additional paper centering ring setup within the main body tube.