I've had a ChargeTI for several years. It stays in my truck and has been very, very useful. I have a smaller PS4 on my keychain. The PS4 does not appear to be robust, but it is built very well.

SH,

Nate modded my Ratchet to make the top edge useful. He also convexed the primary edge and did a nuclear meltdown treatment on the spine. It's sort of like a Graham Razel. The top (perpendicular to the handle) edge is not straight and "sharpened" to a "V". It works well in a scraping motion and saves the primary edge for more delicate work. I like it.