A – The A stands for an “A” section v-belt. This is considered a “Classic” v-belt style that has a top width of ½ (0.5) inches and a thickness of 5/16 (0.312) inches.
119 – 119 inches is the inside circumference of the belt. For A-section v-belts, the outside circumference is found by adding 2 inches to the inside length of the belt. So, the outside circumference of the A119 belt is 121 inches (119+2).
Reference: A119 V Belt
Top Width: 1/2 in
Height: 5/16 in
Length: 119 in Inside, 121 in Outside
Equivalent to: 4L1210, 4L-1210, A119, 4L 1210, A 119, A-119, Dayco AP119, BTQ-A119, A119 D&D Power Drive