CobraGT40

Hi there...I'm new to this forum. I just bought a second-hand QCA Majestic Series spa that is about 5-6 years old. Its has 15 of these air-vent type things on the seat bottoms (resembling the top of a salt shaker) and 5 of them are cracked so I would like to replace them. Only thing is, I'm having a tough time finding where I can get them. Does anyone know what I'm talking about and a place I can get them ? the soa should run fine without them, but I'd like to replace them before I fill it with water. Thanks ! Scott