SVS Soundpath Subwoofer Isolation feet Materials Of Construction: Durable Anodized Steel Outer Shell Elastomer Foot with Optimized Durometer Stainless Steel Machine Screws Subwoofer Isolation Feet Dimensions: Overall Height: 40 mm Shell Diameter: 58 mm Foot Diameter: 53 mm Screw Engagement Depth: 13mm (applies to 20mm length screws) Package Contents: 4 Foot System: Four (4) SoundPath Isolation Elastomer Feet with Steel Outer Shell Four (4) ¼-20 x 20 mm screws Four (4) M6 x 20 mm screws Four (4) M8 x 20 mm screws 6 Foot System: Six (6) SoundPath Isolation Elastomer Feet with Steel Outer Shell Six (6) ¼-20 x 20 mm screws Six (6) M6 x 20 mm screws Six (6) M8 x 20 mm screws