So I'm throwing together an all Solarforce set up. I saw on ebay the P7 rated at 900 lumens for $24.99 and the SST-50 rated at 670 lumens for $39.99. These are from the same seller. I'm confused as why the higher lumen P7 is $15 cheaper than the lower lumen SST-50. I though it was the other way around. Also are the Solarforce RCR123s and 18650s any good? Saw them pretty cheap in Ebay too. Thanks.