Maverick's gadget is the Breaching Torch, which is a blowtorch that you can use to make holes in reinforced walls and reinforced hatches. You can use the gadget anytime and anywhere, but it does have limited fuel.
Clash's gadget is the CCE Shield (Crowd Control Electro Shield). It is completely see through and has a taser which can slow down attackers and do a little damage too. The CCE Shield can be used anytime and anywhere, but the taser does have a cooldown.
