40, the quality of the sound is exactly what I was expectingTo me this is a great acquisition! So worth it I bought A second pair in black. Rad Rover Step Thru 1 fits nicely into this holder. However recently the wood has developed cracks and the finish is wearing off. didnt know until after return date. I expect this when purchasing from third party sellers from China, but not from Amazon itself. These are my second pair of Keen Targhees, they are the most comfortable boot you can buy. Attaching this rack to the seat post is not easy. unbelievable bad experience ! I have to say this mount barely blows in the breeze.