Belt loops are a feature that helps wearers keep a belt in place at the waistband of jeans.
Belt loops were first added to the waistband of the Levi’s 501 jean in 1922 when wearers began preferring belts over suspenders.
The classic belt loop 
Tucked belt loop that’s sewn into the waistband
Jeans most commonly feature five belt loops. Wrangler jeans, though, feature seven belt loops for extra comfort while horseback riding.
To add strength to the construction, some jeans feature double-layered ‘tucked’ belt loops with a smaller loop underneath the larger visible loop, which is sewn into the waistband.
