Varusteleka has updated a popular overall issued to border guards for static duty in extreme temperatures with new materials and features. Now, it’s available in both Finnish M05 Woodland and Snow patterns. Another improvement they’ve made is compatibility with armor and chest rigs. The front can be configured as seen in this photo, allowing access to your gear while keeping it under the coverall.

The coverall is made from 100% polyamide ripstop (70g/m2) with a non-fluorinated water-repellent treatment. The coverall is also insulated with 67g/m2 Climashield Apex which allows you to remain comfortable in temperatures as low as -35°C / -31°F.
Features:

Helmet-compatible hood with a short visor
Adjustable face opening and head circumference
Hanging loop
Removable neck flap
The entire coverall can be packed into the hood
Two front zippers
Wind flaps with hook-and-loop closure
The wind flap can be closed out of the way with its own hook-and-loop
Wind flaps have loops for various attachment methods (see usage methods)
2-way ventilation zippers in the armpits
Adjustable waist with elastic band
Internal suspender loops
Separate zippered fly for field relief
NIR-compliant

This coverall is made in Slovakia by Koutny and comes in three sizes.
I’m told NATO (including US) troops have made private purchases of the coverall while on deployment to Finland after seeing this the locals do it.
varusteleka.com/en-us/products/sarma-tst-l5-thermal-patrol-coverall