You can go to an industrial supply store like Grainger to custom order electrically insulated gloves. That's where I went to get mine - they helped me get properly fitted and find one that was suitable (Ansell Class 0).
Whatever you do, don't rely on Amazon for stuff like this. These kinds of gloves are vetted for protection for only a certain amount of time and you can't rely on random resellers to guarantee that. Careless packaging and handling can also potentially damage the gloves and render them useless, another reason to order directly from an industrial supplier.
Also, don't allow yourself to be careless when operating on a CRT just because you have electrical gloves. Do your research thoroughly and plan out exactly what you need to do beforehand. I haven't gotten shocked yet with mine, but I don't want to put it to the test for obvious reasons.