1.3" x 3.57" small collet intake valves, standard on Austin America, A-H Sprite, MG Midget and later A-Plus 1275cc Mini.
As it is possible, even common, to swap one head for another on 1275cc engine, it is quite easy to become confused, or worse yet, confuse the parts guy when it is time to order new valves. Be aware that if the head has been worked on previously, it may have oversize valves, it may have undersize seats. Unless you are 100% sure what is in your cylinder head, it is a good idea to remove a valve for accurate measurement. There are two lengths used (nominally 3.44" & 3.56") three different keepers, (wide, narrow, and three-groove) and many different head diameters.
12G1316 (Smog-Type), all variations of the 12G940, and the latest CAM head castings all use the 3.56" long valves.
Recommend: 4 x 12G941 per Mini.