Progressive Practice Lock Assortment Set of 8 Educational Aid (KW Keyway)

For locks, you can also think about a progressive set like the one below from GSR Enterprises. It really helped me to progress my skills, although they don't count towards any belts. I will say, they're a bit pricy considering you will outgrow the easiest ones very quickly. https://a.co/d/0dyu5fKi