Since you have an Aegis X, I'm assuming you want a dual battery mod, correct?
As far as Dual batteries go I'd suggest a couple:
Aegis Legend:
I worked construction ~2 years with one of them. It got dropped, smashed, everything. I gave it to a buddy last year to help him get off cigs, he's still using it today. The newer Zeus version is A LOT lighter too, since they used magnesium alloy in it instead of zinc alloy. Def get the version made with that material if possible.
Jackaroo Dual:
I've never owned one. But I own a couple of the single versions, one still NIB if you wanna buy it cheap
. The Single was built like a tank, even better than any Zeus I've ever owned/handled. As long as the battery door on the Jackaroo 2 is solid, that would be my #1 suggestion to you. Oh and the Jackaroo also uses the same magnesium alloy found in the Zeus Aegis Legend version.
If you dont think your mods have to be IP67 rated to hold up to your job (believe me...they dont), then you have other options...
Vaporesso Gen S or the Gen s Ultra (formerly the Gen X)
The Gen S is made of a very durable plastic material. I dunno what the heck it is, but it's damn strong while remaining damn light. It also is cosmetically durable, meaning you aren't gonna scratch/chip the outside of the mod very easily. The aluminum version is also very light and very durable (even more structurally durable than the regular version). However, it WILL show scratches much easier than any of the mods Ive suggested so far.
Vandy Vape Swell
If you can find one of these, they are superb. They're made of ABS plastic. I once had a Vandy mod made of the same ABS caught between a door jam and a heavy steel door closing (i dropped the mod while walking through the door with my hands full. The mod happily took the impact like a champ. One TINY piece of ABS plastic chipped off. The swell itself is also VERY light and compact, prob the smallest of all the mods I've suggested. Oh and the circuit board on the Swell is waterproof too!.
LMK if you're also interested in singles. I got plenty of opinions on them as well lol