Add on to your hamster habitat and hamster cage with Ferplast hamster play tubes and tunnels. The telescopic tunnel can be used to add 4.9 to 8 inches in length to your hamster’s tunneling system. The Ferplast hamster tube measures 4.9 to 8 inches in length with a diameter of 2.4 inches. Ferplast hamster tubes are only compatible with other Ferplast branded play tubes and will only connect onto Ferplast .