Non HP-Calculators using RPN

RPN (reverse polish notation) was used in many Hewlett Packard calculators but was much less popular among other manufacturers.

Here's a list of non-HP RPN units:
 
Manufacturer Owned Models Other Models
Accuron
600

Commodore MM6X
Corvus 500
Elektronika (Russia) mk-61 B3-19M, B3-21, B3-24, MK-54
Magiclic

306
MBO
L-0832

Montogomery Ward

P10
National Semiconductor
Model 600
900, Mathematician, 4615, 4640
Novus (later name for National Semicondutor) 4510, 4515, 650
3500 SR, 4520, 4525, 6035
Omron 12SR
Prinztronic

Programmable Scientific
Privileg (Germany) SR-54NC
Santron

12S, 604
Sanyo
CZ-2901

Sinclair Scientific Scientific Programmable 
RTF (former DDR VEB)
Konkret 600 (identical to Elektronika B3-19M)

See also Nigel Tout's Vintage Calculators Web Museum, the MSDSite and the The Spyropoulos Site.