The Novoflex CANLEI-AF Lens Mount Adapter is the required adapter ring to connect a Canon EOS type camera body to the Novoflex Balpro series bellows system. This adapter ring has the Leica M39 screw mount at the other end, but you will still need the Novoflex #APRO (B&H #NOA35) to go from this CANLEI-AF ring to the bellows itself.