Set of 4 pieces, different diameter (19/20mm) and color (red/black) for you to choose. Suitable for 19mm diameter bench hole. Place directly on the workbench. Made of high quality aluminum alloy, sturdy and durable. Square clamp pad for secure grip. Excellent for milling and cutting and grinding. Product Description Specifications: Product Name: Bench Dogs Material: Aluminum alloy. < p>Color: Red/Black. Size: 28*35*19mm Suitable for hole size: 19mm. Package Content: 4 x Bench Dogs