Aha, I've just realised its a Suzuki throttle tube . That bit that's still visible in the picture is particular to Suzuki. This means that you can only fit genuine Suzuki grips because all after market grips are not designed to fit over that conical flange. That's not to say you cant actually fit them but they just won't look very neat . There is , however, a solution and that is to buy Pro-grips that come with a Suzuki adapter or at least some of them do and there no guarantee there will be one in the box unless you buy over the counter. I'll nip out to my shed and take a pic to clarify what I mean . The other solution is to fit a non specific throttle tube that will accept any grip. Ok, here you go , that black plastic ring with the textured surface is the bit I mean. By the way , those Oxford Fat Grips are great .