20mm or 1/64 most are from the M2 Machines, Ground Pounders sets. I like these better than Matchbox/Hotwheels. They look beefier and cooler, hotwheels look puny. The dirty ones are also M2 series, Projects. I love them because they have that rusty look. I've been using parts from Stan Johanson and Dark Future weapon spures. Thanks for the Birthday wishes.