I would wait for a LF rep to answer.
The last time I ordered Riva 901s from LF, I got a mixed batch. I ordered 3 batts. One was one of the old EM models, as it had the LF logo and the on/off feature, but two of the
batteries had no logo and were unsealed (big hole in the center post). When I contacted CS about the two unsealed
batteries, they sent me out what I assume is now their current stock, which were sealed but lacked the on/off feature.
The listing for Riva 901 batteries on the LF website makes no mention of an on/off feature, so I would guess that the feature is not available. Again, I would wait for a LF rep to answer. I am sure ImYourSalt will be along shortly.
