Noco Genius 1
$40.00
The NOCO GENUIS1 works with 6-volt, 12-volt, lead-acid, lithium-ion, maintenance-free gel and AGM batteries. That's pretty much all of the batteries.
The needle-nose style clamps are great for reaching terminals in tight spots, and they are removable, if you want to rock a pigtail whip.
It also repairs batteries when it detects sulfation.