Missing flange nut that holds the blade on. Replacement part fairly cheap online to replace.

to The RIDGID 18V Cordless 4.5" Angle Grinder R86041 is a high-quality power tool designed for a variety of grinding tasks. Powered by a reliable 18-volt lithium-ion battery, this brushless angle grinder offers convenient cordless operation without the need for a power source. With a 4 1/2 inch disc diameter, this grinder is suitable for a range of cutting and grinding applications. Made in China, this tool is part of the trusted RIDGID brand, ensuring durability and performance for all your project needs. Includes handle grip