The class of the ship is never mentioned in the series, though they are referred to as "Collectors Ship". The ship is the primary ship used by the Collectors. No information about its capabilities is provided in the series, though they are seen escorting heavy cruisers. In season 4 "The Torment, The Release", 4 ships engage the Andromeda Ascendant but as the ship's weapons codes are provided to the Andromeda crew all ships are destroyed. They do appear to be very well armed though.
They also appear in "The Heart of the Journey (Part 2)". Once the Spirit of the Abyss is destroyed some Commonwealth ships are seen exiting through slipstream which indicates that the ships are used by High Guard.