Mars Trigger MP5 Lower w/ AR Super Safety Trigger PTR 9K Black. Precision-machined components for HK SP5 platform. Ready to install for immediate use. Specifications for Mars Trigger MP5 Lower w/ AR Super Safety Trigger: Manufacturer: Mars Trigger Color: Black Features of Mars Trigger MP5 Lower w/ AR Super Safety Trigger Complete lower assembly AR Super Safety integrated MP5 trip bar pre-installed Ready to install Package Contents: Mars Trigger MP5 Lower w/ AR Super Safety Trigger What firearm models does the manufacturer say Mars Trigger MP5 Lower w/ AR Super Safety Trigger is compatible with? The manufacturer says that Mars Trigger MP5 Lower w/ AR Super Safety Trigger is compatible with PTR 9C Heckler & Koch MP5K Heckler & Koch SP5 PTR 9R Heckler & Koch SP5K Heckler & Koch MP5Mars Trigger A030-ASM-005-V01: MP5 Lower w/ AR Super Safety Trigger PTR 9K Black