Backing plates, or back up plates are used as the attachment method to connect your buffing pad to your polisher or buffer.  Rotary Backing plates are very universal, with 95% of tools in the US market utilizing a 5/8-11 thread.

All of the Oberk Rotary Backing Plates are standard 5/8-11 and are a premium Molded Urethane that is Made in the USA.

European tools, such as the Festool (one of the only tools in the us market) have a 14mm thread and are much less available in the United states. 

Dual action or DA backing plates are a little more specific to the machine being used. We currently do not offer any of the DA Backing plates for any tools on the market. BACKING PLATE REFERENCE IS BELOW - 

Flex XFE-15 - Special plate only available through Flex Tools

Rupes - Specialized and weighted for Rupes tools specifically and available from any Rupes Authorized distributor -

Bolt size - 6xM4

Porter Cable - Not used nearly as much

5/16-24 thread - many standard DA machines like the old Griots GG6 and others use this thread and have multiple options and sizes available at most distributors. 

Griots BOSS - also utilize a M4 bolt like a Rupes for most of their tools.

Always check owners manual to ensure proper bolt size, length, and thread