dhd is correct, I have a few telescopes and a few kicks and they are NOT large enough to take an 18650+kick....But, they will take an 18490/18500+kick...... and they work quite well together.....
I also have a chrome bolt/w chrome button, with the old small wiring and I've had no trouble with an 18350+kick, and I've been using that combo regularly for quite some time now!