This product is awful and painful to use, the rods on the sides are too close together so the spiralled surface just digs into your penis.
Trying to tie the strap below the head of your penis is extremely painful and uncomfortable, it will stick and rub against it unpleasantly, if you use lube then it won't stay in place.
The screws to increase the length are an awful idea as it'll dig into your penis as you try to screw, even still the length that you can extend the screws doesn't even increase much and only goes a couple of centimetres.
I highly do not recommend this product, use a penis enlargement cream if you want a bigger penis.