Chassis mounting phono sockets fixed to paxolin panels. Fixing holes are 3.75mm diameter & the phono sockets require 8.5mm diameter cutouts if rear-mounted. Available in the following configurations Type No. of Dimensions Fixing Socketsocketsof mountcentrescentresmmmmmm Twin 256 x 224820 Quad 476 x 2465142 Square 449 x 3640 x 2615 x 166-Way 665 x 3655 x 2615 x 168-Way 880 x 3670 x 2615 x 16