Memory card SD/MMC write blocker

What're you looking to spend?

The Weibetech Media Dock is tiny, is bus-powered, and uses standard cables. Any USB WB should do though.

We use Digital Intelligence's UltraBlock Forensic Card Readers because they came with our FRED's. If you purchase them alone HERE, they're $80.

While I was pulling up how much they cost, I stumbled upon this helpful paper published by Marshall evaluating forensic card readers. I think it's always helpful and safe to have something that verifies your claims that your method of write-blocking actually works (other than yourself, of course).

Any USB WB should do though.

I support that. If you have an USB write blocker, just connect any card reader to it and you're done.
In fact you may try also a software writeblocker and connect the reader to your computer USB port.