You mean what type of gear?
You can use almost anything..... Obviously it should be oil based tho...
Any kind of test, tren, eq, deca.... etc.... All are fine for site injections.
How effetive are they??? Do you mean will they make your muscle in that area grow..... Well not really.... I do believe that it will help to strecth the muscle fascia and possibly allow for new growth easier tho.