Cosplay Faux Brass Knuckles, dimensions 104.07mm x 35.12mm x 17.95mm or 4.10inch x 1.38inch x .71inch - This model is currently designed to fit most large hands. Scale up or down as needed or get me your pointer finger ring size and I can make the adjustment for you.
Can be printed in most materials, if you plan on casting them in some other material- let me know and I can give you a model with sprues so it cast's correctly.
Please keep in mind, these are designed for cosplay use only. Even so, some states dont care if they are plastic or not. Please check local laws before taking them out of your home. I can tell you for certain, some states like Michigan dont care what material they are made from. You could potentially find yourself in trouble even with a soft foam copy. Personally I've made quite a few resin copies and never had any trouble here in the south. Please do your due diligence.
Any questions, let me know.