The Sirio Mag 145 magnetic base is the larger version of the Mag 125. It is designed to accept a 3 / 8 threaded whip and comes complete with cable and PL259. Sirio mag mounts for amateur or CB aerials requiring the so 239 fittings. Very high quality, Sirio is well known for its aerials and accessories. 160 mm in diameter, which makes it perfectly adequate for CB aerials up to and including the Sirio megawatt 4000 and similar sized amateur aerials.