Chelle, you'll need to get products like that from your local vet, and he/she will also be the best person to advise you on which will meet your needs.
There are two things to be careful of from my limited experience though. The first one is to make sure the vet knows they are Shetlands and adjusts the dose accordingly. When we bought our Manx Loaghtans, the vet sold me one syringe of wormer for each sheep. However, when I looked it up, I only actually needed 1/3 of the prescribed amount for small primitives.
The other thing is to be careful of the quantities. I ended up buying flukicide for 200 ewes, which was firstly expensive, and secondly 98% wasteful. I went with it at the time since it was the only option presented to me, but in hindsight I should have done things differently, and possibly also used a different vet!!
Hope that helps!