Evolution Airsoft have AEGs under the Lone Star brand that carry the Electronic Trigger System (ETS) and SAT & Gaming Airsoft explains to us what this is all about with the Lone Star Border Patrol SBR ETS AEG (in Italian)... "Evolution Airsoft seeks to carve out a place among the most avant-garde homes by offering an M4 equipped with a series of modern and cutting-edge mechanical and electronic solutions. The Lone Star Border Patrol is updated with their ETS electronics becomes a medium range rifle with an interesting value for money ratio."