Shingle eater is the most valuable tool when ripping shingles off the roof. When this product first came out, I purchased several of them. It made ripping the shingles off ten times faster than the old fashion way. I used to have to use a little shovel before this product came out. Using a little shovel made the job take more time to do. Using this product I can usually get the shingles off in a matter of hours. These tools are made by Shingle Eater MFG. They are very durable and do not bend. There lifespan is depending on usuage usually last is two years, and that is basically using it everyday. I usually use the larger ones, it is easier on the back, cuts out alot of bending. Roofing can be very rough, these things have fallen off the roof many times and they are still durable. There are no parts to remove and replace. The construction of them are the best I have seen. They will definately increase any roofers productitivy regardless of the roof pitch. You can choose the shingle eater that is right for you regardless of your height and size. They come with four to ten teeth. I prefer the ten tooth overall. That is the best for large jobs. For smaller jobs I prefer the four tooth shingle eater. Shingle eater stands by their product. Shingle eater has been in business for twenty five years, and after you use their product you can see why. This is a product valuable to the roofing industry. Easy to find they are available at most place's that sell roofing materials. I give this product ten stars.