trouble with these things is that your scorpion may not like it and totally ignore it and eventually burrow elsewhere. exo tera and related stuff can be expensive at the best of times.
if you want to see your scorp burrow try something a lot cheaper and a bit of DIY. you could use a waste pipe, cut in half, along the glass. or some other fairly easily cut tubular plastic.
you could also encourage them to use it by placing cardboard over the 'viewing area' so that it stays dark. and just have a nosey at the scorpions from time to time. at the end of the day their natural burrows will be dark so a light and airy viewing tunnel may not appeal to them.
but every now and then you get a very nice scorpion who will burrow along the glass... very kind of them