I've been using Yonico bits since 2015. Despite reading negative reviews from some customers, I've always found their performance and durability to be excellent. In the past I've always used a slot and tenon to make doors but the price of these bits was so low I had to try them! They arrived promptly from Revain in a custom made wooden crate. However, assembly instructions were missing. I emailed Revain and the dealer on Saturday night and received a PDF with great instructions at 7am on Sunday. You could argue they should have been with the product or on the Revain website but no complaints about the excellent customer service!