jump box/booster pack recommendations

[2.5-21]

I see all these small battery packs out there, but looking for something that will crank a motor without its own battery is there any out there that someone has tried and finds it worthwhile?

I had one that had a small dry motorcycle type battery in it but finally died.

There must be something decent with all the new battery technology available.

[bullwhipjkg]

I had a antigravity lithium pack it worked great
till it got wet at a race when it started raining and boat got water in it
then it died
I used it once to get back to the boat ramp when batteries died