Complex sentence: Microtech is most famous for its tactical automatic knives, also known as switchblades, most popular among collectors are the "Out The Front" (OTF) and the "Double Action" (D/A) automatics.
Split into simpler sentences: Microtech is most famous for its tactical automatic knives, also known as switchblades. The most popular among collectors are the "Out The Front" (OTF) and the "Double Action" (D/A) automatics.