Check the listing for details. SELF-INFLATING KEY RING BUOY FLOATING BOAT KEYRING - Float/Marine/Water/Keychain. Condition: New. Listed at 18.71 USD. 1 x Self-Inflating Boat Key Ring Buoy. Go ahead, grab yourself a bargain! For single use only, so keep a spare on hand or in the boat! Within 30 seconds the inflated tube carries keys to the surface for easy retrieval.