Check the listing for details. BMX, BICYCLE, VOLCANO WASHERS for Cap Head screws, 6mm, 10mm (3/8") - COLORS. Condition: New. Listed at 13.98 USD. Aluminum VOLCANO WASHERS for Female Axle Hubs (fits Cap Head Screws / Allen Bolt Style) SOLD AS A SET OF 2pcs (you will receive 2 volcano washers for each item purchased Available to fit mini/ junior female axle hubs that use either 6mm, 10mm, or 3/8" bolts. Note: 10mm & 3/8" use the same size volcano washer) These allow for a clean and cool look to hide your axle bolt. Please make sure you check and order the correct size. (6mm bolts are smaller than the 10mm & 3/8") Specs of 6mm volcano washerOD = 19.84mmID = 11mmWidth = 10mmSpecs of 10mm (3/8") volcano washerOD = 23.96mmID = 15mmWidth = 13mmNote: Unfortunately if you need to return this item due to ordering the wrong size, you will be responsible for the shipping charges.