2 pieces of plastic rail fixed casters designed for smooth movement on rails. They provide quiet operation to keep environments peaceful while in use. Key benefits - Smooth rail movement for stable, easy maneuvering - Quiet operation reduces noise in homes, offices, kitchens, and workshops - Universal wheel design fits a variety of small carts and furniture - Brakes deliver reliable stopping power when needed - Ideal as replacement casters to keep small carts and furniture in good working condition Product attributes - Material: plastic - Type: fixed casters for rails - Quantity: 2 pieces - Compatibility: suitable for a range of small carts and furniture with rail systems - Performance: smooth motion on rails, quiet operation, with braking capability Use scenarios - Replacing worn or absent casters on a rail-guided service cart in a kitchen, workshop, or lab - Upgrading a small cabinet, workbench, or mobile workstation that operates on rails - Replacing casters on a classroom, office, or light-duty shelf cart that requires quiet movement and brakes This description stays consistent with the original specifications: two plastic rail fixed casters designed for smooth, quiet movement on rails, universal compatibility for small carts and furniture, braking capability, and use as a replacement part to maintain good working condition.