Hi i use a Profi D-CAT CHAIN ALIGNMENT TOOL. i have had mine 5 years still on the same battery. you can buy them on ebay or just goggle them. do not buy the cheap ones, these should cost �50. i have just checked on ebay and they are still selling at �50 delivered. they come in a small blue bag so you can just put them in your tool box a they are fine. hope this helps. i always use mine after do the chain just to check its right. and 50% of the time the blocks on the bike are out by a turn or two. all the best