One of the most effective ways of gaining higher levels of traction is by lowering your tyre pressure. This increases the tyre footprint, mainly the footprint length than width is increased.
A lower tyre pressure will enable you have higher levels of grip from mud to snow to rock. There are many different products available. The most common, high quality tyre deflator that I have come across is the ARB tyre deflator and the EZ tyre deflator. The latter, im pretty sure someone on this forum sells them at decent prices.
The level of how much you can lower your tyre pressure varies from tyre to tyre, and there are even aids like bead locks to enable you to lower your tyre pressure even more to enhance your levels of traction and prevent the tyre coming off the wheel when off road.
I generally run My tyres @ 38psi front, 40psi rear on the Terracan and when I think I need that extra traction from lowering my tyre pressure, I lower the pressure between 18-15psi.
The dangers of lowering your tyre pressure is that if you lower it too much, and the terrain is very uneven or poor, there is a chance depending on how aggressive your driving is, that the tyre can come off the wheel.
The other hazard of lowering your tyre pressure is that your tyre side-walls are more likely to pick up damage. Most Off Road based All Terrain tyres and Mud Terrain tyres are reinforced to prevent this from happening, but If you run All season or M&S tyres like I do, there is that chance that the side-wall could become damaged or even ripped open.
Most important of all is that once you have lowered your tyre pressure & travelled your route, it is imperative that you re-inflate your tyres to their factory pressure before venturing back on to the road.To inflate your tyres you will need a proper Tyre inflator.
Again there is a large variety of models and types to chose from, but most operate the same.
You have your pump unit, that either plugs in to your vehicle 12v socket or connects on the the battery. You have an air filter, air hose and connector and a switch, usually mounted on the side of the pump or base. .
I have used the ARB Air Compressor / Tyre Inflator & the T-Max Tyre Inflator/Deflator. Both operate in the same way, offering similar inflation pressures and inflation time. What sets these apart from the Halfords & Generic inflator's is their higher quality parts, durability, heat diffusion, pump pressure and tyre inflation speed.
I personally favour the T-Max pump, mainly because it does what it says on the tin and it is good value for money. It has in the past inflated my 4 tyres 6x times in the same afternoon, when crossing a large area of terrain and roads.Like the Recovery Rope, Make you have it in your vehicle before you leave, especially if your planning to lower your tyre pressure....