Flat Top to Button Top Battery Adapter

These adapters are great for the following uses:
 
• Allowing the use of flat top batteries in devices that require button top.
• Stacking these extends a short unprotected battery to fit into devices that require a long protected battery.
• Fits in between two flat top batteries so they are able to connect in series.
 
Size options:
 
• 18mm = 18650
• 21mm = 21700
• 26mm = 26650
 
I use these all the time in torches that require a long protected battery. Instead of buying an expensive protected battery for your torch, you can often just use 1-2 of these adapters with a standard battery.
 
Please note that some torches have no low battery voltage protection built-in, and require the use of a protected battery.