I got my hands on a MAGPUL EMAG so I bought it for my collection.
The EMAG is the export version of the PMAG, optimized for foreign weapons:
Magpul also offers a magazine called the EMag (Export MAGazine). It is a lightweight 30-round 5.56x45 NATO polymer magazine that features a number of aesthetic and functional changes from the PMAG. While the EMAG remains 100% compatible with the AR15/M16 platform, its unique geometry is optimized for foreign-made weapons such as the British SA-80 (L85A1/A2, L86A1/A2, L22A1, L98A1/A2), HK 416, M27 IAR, and others.
EMAG features the same dust cover as the PMAG GEN M2 Dust Cover and can be stored on the magazine's floorplate to prevent possible loss. It has large dual-sided windows with numerical indicators added to the body to identify 5, 15, and 25 loaded rounds.
It shows how close the TK "30mag" copy really is, even the texture of the plastic and the feel is similar.
Sadly the EMAG does not fit into the TK M4. It can be inserted as long as the bolt is pulled back, but it will obstruct the mag release catch and the bolt.
This is strang as a standard M16 aluminum mag fits and allows the bolt to travel. Anyway i did not yet try to cycle TK rounds with another magazine.