Ball and socket type grill guides. Simply drill the appropriate size holes for press fit. To use, simply drill a 7/32" hole for the pin side and an 11/32" hole for the socket side. Can be used with grills as thin as 1/4". Set includes 8 male and 8 female pieces. Overall length of male is 11/16", overall length of socket is 15/32". Flange for both male and socket is 1/2".