Very different with later Chinese webslings, it should be designed for Chinese type 54 PPS-43 automachine gun

the writtings on the belt is“7.62公厘冲锋枪枪背五七年带 ” means " 7.62mm Submachine gun sling"

"海11/3 五七年一季度制"

means "made in 1st quarter 1957" by the arsenal "海11/3 "