Positron straight gate 210153 / 210261 and bent gate 210154 were recalled by Black Diamond in February of 2016. If you believe that you might own any of these products, read through this safety recall notice to figure out your next move.
The Black Diamond Positron is a good medium-sized carabiner for sport, trad, or top rope routes. The stand out feature being its easy-to-unclip keylock design. It comes in both straight and bent gate versions. The Petzl Spirit Straight Gate and Petzl Djinn Straight Gate are its main competitors, as both have a similar solid gate keylock design. These other biners are a little lighter, a little easier to pull rope through, and they have grooves in the gate that make them a little easier to do reachy clips. Overall, we prefer the Spirit, but the Positron is much less expensive ($7.95 vs $9.95 for the Spirit). Since the Black Diamond Positron also is a great biner, we wouldn't hesitate to recommend it if you are on a budget. If you just want the most carabiner for your money, it's hard to go wrong with the Mad Rock UltraLight Bent Gate.
Black Diamond has confirmed some changes to the Positron for this season. Keep reading for more info!