Of course, any portable (hand held) that uses rechargeable batteries could be called a "rechargeable portable laser".
"RPL" is an Optotronics product line. The RPL starts out as a Viasho (OEM) unit, but has better components, undergoes testing and quality checks, and is even hand polished. Read the
specs on the Optotronics site and note the divergence, diodes, long warranty and other details. That is what makes an RPL.
You can also look for threads by Jack (bootleg2go), the owner of Optotronics. There are several where he explains things. Often people call other hand helds (such as a generic Viasho) an RPL, but it's not an RPL until Jack is finished with it and it's sold by Optotronics.
..and yeah, I own two of them, so I can tell you it's not BS. Also, the customer care one gets from Jack is unparalleled.