They are great for a couple of reasons. Number one they provide a consistent draw of the string which is crucial to accuracy with the crossbow. Cocking the bow by hand can be done but often you can cock the bow slightly off center of the string, as a result crossing left and right issues. The second reason is that they make the bow a lot easier to cock. The ACCUdraw 50 cuts the draw weight by 50%. Most able body men have no problem cocking the bow with the ACCUdraw 50 and is my choice on my bows. The ACCUdraw has a crank type geared reduction draw that allows even a small child to cock the bow. It is a little slower than the ACCUdraw50. Neither of them get in the way when you shoulder the crossbow. At least they don't for me and most other guys as well. Hope that helped.