I do bodywork and fix cars for a hobby, I have done around a dozen car and trucks, in the past I used dura-blocks, my current project is a 82 elcamino. I thought it was ready? boy was I wrong !!! tried these and what a night and day difference. I blocked the hood first and found low spots and high. sanded with these to 600, I can now say its ready! very pleased with products! YES, worth the investment !! thanks for a great products!