Bayonet Cap (BC) [B22] to. Light Bulb Splitter Adaptor/Extender/Holder. B22 to 2x GU10 adaptor is 80mm high by 90mm wide (22mm bayonet cap to 2x GU10). ««« A “MUST HAVE” for anybody who wants to replace a single B22 bulb with 2 shining GU10 bulbs.