Waxman Titan 6" Thermoplastic Rubber Swivel Caster Kitchen Measuring Tools Grooves on the lid are

Grooves on the lid are designed to stack multiple of storage bins securely to maximize limited storage space and create a customized storage solution

or back alley boxing matches

The versatile design is rated for use in walls and under raised floors and is flame retardant for safety

which stretch as you move

Waxman Titan 6" Thermoplastic Rubber Swivel Caster Kitchen Measuring Tools Grooves on the lid areTitan Casters 6" Thermoplastic Rubber (TPR) Swivel Caster is a shock absorbing wheel that provides good floor protection and a smooth, quiet ride, leaving no marks behind. With a 500 lb, load capacity, this chemical resistant TPR caster works well in industrial settings: workshops, garages, laboratories, food service. Swivel casters maneuver tight spaces and respond immediately to sudden direction changes. Replace worn out tires on flatbed platform