The sonic broadheads are a fixed 3 blade that group better then my thunderheads. cut on contact. one inch. made by american broadhead co. here in my state.NH...just down the road. the archery proshop here had input on the design. anyone try them? I spent the $37.00 and was happy. package of 6...although I was a little upset to learn replacment blades will not be aviliable until mid. Nov. or so.