All Ultrafeed machines use two cogged belts — one for the jack drive and the other for the balance wheel. This 18.6" belt is for Ultrafeeds equipped with MONSTER II or PowerPlus Balance Wheels. These belts do not stretch or slip.
Toothed balance wheel belt. To select the correct belt size-measure your current belt by folding it in half. Double the distance from inside one end to the inside edge of the other. Or wrap a string around the drive pulleys of your machine and measure the string length.
Some belts have a number on the outside such as 1934 which means it is a 19 3/4" belt.