This is the Hobby Products International (HPI) M Compound Radial Tires Wide (31mm) Width for Touring Cars and Sedans. Radial Tread and Medium "M" Compound Fits Touring type cars from Kyosho, Tamiya, Yokomo and the HPI RS4 using standard width wheels Fits Wide (31mm) Width Wheels Two Radial M Compound Wide Tires Two Grey Foam Insert Strips Outside Diamter: 2-9/16" (2.5") (65mm) Inside Diamter: 1-15/16" (1.9") (49mm) Width: 1-3/16" (1.2") (31mm) Glueing Tires to Wheels with CA Glue Such as GPMR6001. Glueing the Foam Insert Strip with Contact Cement 31mm Width Wheels . Writing on the sidewall says "HPI and Japan" on both sides. Other versions available: HPIC4512 4512 M Compound Radial Standard Width HPIC4513 4513 M Compound Radial WIDE Width HPIC4540 4540 Super(Soft) Compound V-Groove Standard Width HPIC4514 4514 Pro(Very Soft) Compound Radial Standard Width HPIC4490 4490 Pro(Very Soft) Compound X-Pattern Standard Width HPIC4415 4415 Pro(Very Soft) Compound Slick Belted Standard Width AXY 10/9/99 ir/jl &