These are all marine rated DC circuit breakers, they are ignition protected and weatherproof and come in both panel and surface mount styles. The two different case types represent a heavy duty model and a lighter duty model. The heavier duty model is the Bussmann 187 Series and has larger terminal studs and a higher interrupt rating. The lighter duty model is the Bussmann 185 Series with a lower interrupt rating, smaller terminal studs and more modest price tag. All are available up to 150 Amps rating and the 185 Series goes up as far as 200 Amps rating.
When selecting a primary circuit breaker you might like to read my blog post explaining the ABYC standards relating to interrupt capacity.
Panel mount circuit breakers are designed to be mounted in a panel so the wires are connected from behind and the only the face of the circuit breaker appears in front of the panel. Surface mount circuit breakers just screw to a bulkhead and the wires are connected to the front of the breaker