The Samsung 25r is one of the longest standing trusted 18650 batteries on the market. The 25r comes at a slightly lower price so are chosen by a lot of people running multiple battery systems to keep costs down slightly. With a 50A max pulse draw capacity they are still a fantastic choice for high load applications.
1x Genuine Samsung INR 18650 - 25R High Drain Lithium Ion Battery. 2500mAh capacity - 20A Continuous Discharge
Efest 18650 - 2500mah High Drain Lithium Ion Battery (25EF)
Sanyo 20700B 4000mAh Lithium Ion Battery
Efest 20700 3100mAh 30A Battery
Samsung 40T 21700 4000mAh Lithium Ion Battery