These Jim Dunlop slides are chrome or brass and come in a variety of models.

J220 is chrome, medium, suits ring size 9. Dimensions: 19mm x 22mm x 60mm 

J221 is chrome, short knuckle, suits ring size 9. Dimensions: 19mm x 22mm x 28mm

J222 is brass, medium, suits ring size 9. Dimensions: 19mm x 22mm  x 60mm

J223 is brass, short knuckle, suits ring size 9. Dimensions: 19mm x 22mm x 28mm

J318 is chrome, medium wall, extra large, suits ring size 12.5. Dimensions: 22mm x 25.4mm x 51mm

J320 is chrome, medium wall, extra large, suits ring size 12.5. Dimensions: 22mm x 25.4mm x 60mm