Mk I Suit

The standard issue spacesuit that HMRC / ARM members start out with, a grayish airtight spacesuit with light armor to prevent puncture or tearing from environmental hazards. It has your name printed on the chest, a metal helmet and faceplate and a heat exchange system on the back. 
Protects against cold and vacuum. Has a built-in communications system, light lamps, a small generator, and a few other bits and pieces, but nothing special.
The helmet has a solid metal visor with a camera on the outside. On the inside of the visor is a screen which displays the camera's feed. The visor can be lifted away from the face, revealing a protective glass window.
The light lamps can be removed from the helmet, allowing other electronics to be plugged into the suit's power system.
Two 'fins' of conductive material and a large heat-exchange coil are on the back of the suit. These radiate excess heat that accumulates in the suit. If they are destroyed or damaged, the user will rapidly boil themselves to death. In near-absolute-zero conditions, touching the heat fins to something can have catastrophic results, depending on the boiling point of the material touched. That means that resting your back on frozen oxygen or taking a dive in liquid helium can have some explosive results...
They're strong enough to stand up to ordinary knives and simple things like that, otherwise you'd be screwed with every stumble. 
Things you can control through suit menus (some features might need roll to discover):
*Lights
*The monitor on faceplate
*Internal temperature
*Clocks
*Tetris
Official Description:
A very simple thing, it's basically a light spacesuit with a hard metal fishbowl helmet. Has very good insulating properties (protects against heat, vacuum) but no armor whatsoever. Comes equipped with some basic tools and gadgets. So, it's not that great, but at least it keeps the void out.
Steve's description:
Those Mk I suits of yours will protect you against vacuum and pretty much any changes in temperature, as well as offering a degree of radiation shielding. What they will not do is stop a bullet. Crushing forces, maybe, laser, for a very short time, but not a puncture. And in the event of a puncture, that protection against vacuum and temperature goes away. To put it simply, you will be flash frozen before you even realize you've been shot. Try not to be punctured.
Also, that suit has a heat exchange coil on the back. Don't go touch it or pressing it on anything. Touch that thing to some ice in Near Absolute zero conditions and it will be like a grenade going off just behind your head. 
They're basically a more form fitting space suit with a few patches of metal plate armor scattered about. The helmet is a metal shell over a plastic bubble with a faceplate that can be opened or closed. When the faceplate is down, cameras on the outside project a feed onto a screen on the inside, allowing for things like light amplification. When you flip the faceplate up it's just like looking out a window. Probably a good idea to keep the plate down for the little bit of protection it adds.
Response to a question about insulation/shielding:
Thermal insulation is a combination of extremely good insulation, meta-materials, and heat conducting systems to keep the inside cool and not fatal. 
Radiation shielding is done mostly through the same material and a thin layer of dense foil.  It's not very good.