This billet aluminum timing tab has a built-in self-powered LED timing light or car battery hookup. Permanently mounted so there's no need for additional timing lights. The hands free design allows one person to set timing! U.S. Pat. No. 7,503,209. Features : - Fits 1955 to 1997 Small Block Chevy Engines 283-400 Using a 6-1/4 Inch Balancer. - Made from Billet Aluminium. - Black Anodized. - Sold Each. - 3V Lithium Battery Included. Specs : - This billet aluminium timing tab has a built-in self-powered LED timing light or car battery hookup. - Permanently mounted so there's no need for additional timing lights. - The hands free design allows one person to set timing! - U.S. Pat. No. 7,503,209.