The Sten gun was a cheap and nasty weapon, designed for rapid mass production at low cost. Whilst cheap, this supplement certainly isn't nasty, continuing the very high standard shown in all Day After Ragnarok products.
A quick history of the weapon is followed by a basic description of it's construction. Next comes an overview of the pro's and con's. Stat's for the two most common version are next, along with some optional rules that capture the gun's idiosyncrasies. There are even adventure ideas, and suggestions for magical enhancements.
Overall, this is an excellent supplement for it's cost. Whilst not perfect (there's no mention of the mark 4, for example) it gives a lot of background information and rules mechanics. Some of the ideas here could be used in other WW2 type settings. And, as always, the production standards are very high.