Sometimes known as a 'Boston Valve' this two-way inflation Bestway Screw Valve is mainly used with Bestway Dingys and air mattresses but is also used on some Bestway Pools. It screws in to fit a 2cm diameter hole. If you are unsure which valve to purchase you can call the Bestway Helpline on 0800 612 0457. Please Note: We reccommend you measure the hole prior to ordering to make sure it is the correct size and part.Does Not Fit The Regatta AirbedsSafety Information:Warning. Not suitable for Children under 3 years. Warning. Only to be used in water in which the child is within its depth and under adult supervision.