Hi guys i have a doubler and adapter fitted to mine,the adapter is that good a fit i didnt bother with the silicon makes a big difference,also a coaster on the focus ring is a must as its very stiff,the T20 ir is great if anything a tad too much light,im waiting on a 3 stage one which will give 3 brightness settings and and will see how that goes, a spotter in my opinion is a must as the field of view isnt much, guys are using filters on them to take the glare off the screen these are 55mm and fit over the doubler then the cover over that,havnt tred this yet so cat comment,but for the money i think its great,and i use it uring the day without any problems,dont think you will be disappointed.