These 4" mini can enclosures fit 7/8" - 1-1/4" round tubing or 1" square tubing. Tough ABS, weatherproof empty enclosures with slotted mounting holes for different bolt patterns. Durable, stainless steel push-type connectors. The set includes acoustic poly-fill for the clearest sound and all mounting hardware. Cans accept all Kicker 4" component speakers and horns.