VideoRay thruster cartridge seals come in two form factors and three colors.
1. Clear - these are for Pro II era ROVs. These fit inside the thruster cone and need to be removed to be inspected.
2. Green - these are the first version that can be inspected without being removed. These fit all thruster shafts except the Pro II era, GTO horizontal shafts and Pro 4 vertical and horizontal shafts.
3. Blue - these have a slight blue tint (which almost appears clear, but their shape is different than the clear cartridges). They fit all thruster shafts except the Pro II era ROVs. They are standard on all current models.