Dual-side Adjustable And NO SewingThe strap is adjustable on both sides of the 20mm plastic side release buckles.The regular quick side release buckles require to stitch one side. No sewing is needed with these 20mm Quick Side release plastic buckles Because the male and female side of plastic buckle have both two slot to feed the strap through. Simple to useVery easy to replace the bad buckles or regular release buckles on backpack,rucksack, helmet strap,parachute,backpack,fanny pack,belt,Bayby carrier,waist pack,dog collars,harnesses,pet collars,boat covers etc, Only Insert the strap into two slots on each side of these side release buckles.Don't need sewing. Hand Wash Fastening: plastic buckle 20mm-4sets StrongThe plastic buckles are made of high Grade plastic. These 20mm plastic buckles tensile tests,the plastic buckle clips can withstand a pulling force of 25kgs(55lbs),hold tension well.