28mm LH. The 3010-19-41, 3020-19-41, 3030-19-41 & 3040-19-41 Backset Adaptors from dormakaba (formerly known as Kaba) is designed to suit the dormakaba Simplex 3000 series of mechnical digital locks. This handed adaptor is available to suit a variety of backsets.. Suits dormakaba Simplex 3000 Series. Complete mounting backplate assembly kit. .