The EPM1-S RX is a slight revision of the venerable but still industry-leading PTS EPM1-S 170 round 20R length short M4 magazine. The primary revision is brand new tooling for the internal shell which leads to more precise dimensions and smoother bb channel. The EPM1-S RX internal shell is distinguished by Its grey color and EPM1-S RX markings on its surface.
The EPM1-S RX retains all the same features and technologies of the original EPM1-S:

Capacity:
170round BBs capacity and its legendary feeding consistency and reliability.
Dupont Zytel Polymer Shell:
This extremely rugged polymer capable to withstanding considerable rough field use and abuse.  
Angled Basepad:
Made from the same rugged Dupont Zytel polymer as the magazine body, the angled flat bottom of the basepad allows you to rest the gun on any flat shooting surface for greater shooting stability.  The small and unobtrusive front lip ensures correct indexing of the magazine and aids in drawing the magazine out of a magazine pouch.
Base Dot Matrix Pattern:
This feature allows for personalized magazine marking with a marker or paint pen for ownership identification, magazine load distinction, etc.
A Wide Range of Compatibility:
The EPM1-S RX is compatible with Version 2 based M4 AEGs by TM, KWA, PTS PDR-C, PTS ERG series, PTS Masada, G&P, the VFC 416, the CA 416, AMOEBA AM Variants, and many more.
Continuous Mag Well Guide:
This design reduces snagging when drawing from or inserting into pouches or the rifle mag well.
Signature EP Texture:
The magazine features a positive texture for better grip and tactile feel.
Enhanced magazine follower:
The result of our design collaboration with Deranged Designs, this follower greatly improves the BB feeding speed and consistency and completely preventing BBs from sliding past the follower and creating a jam.
The Fuel Gauge window:
The unique orange mag level indicator lets you immediately know if the magazine is filled to capacity, its approximate remaining capacity, or if the magazine is empty. When the magazine is fully loaded, the mag level indicator will show at the top of the window. As you fire the BBs out of the EPM1-S RX, the orange indicator will travel down the window until it reaches the bottom, indicating that the magazine is empty.

COMPATIBILITY

• Tokyo Marui Style AR-15 AEG Airsoft
• G&P AR-15 AEG Airsoft
• KWA AR-15 AEG & ERG Airsoft
• PTS ERG AR-15 Airsoft
• PTS Masada AEG
• PTS PDR-C AEG
• VFC AR-15 & HK416 AEG Airsoft
• CA AR-15 & 416 AEG Airsoft
• AMOEBA AM Variants AEG Airsoft