Incudes 1 X QS-50 Female Receptacle & 3 X Q50 Male QR Plates Both QS-50 & Q-50 Feature 3 Set Screws. Includes 4mm & 2.5 mm Allen Wrenches Swap Heads & Columns in Seconds. Twist the Lock Collar to Secure. QS-50 Weight 63g. Outer Diameter 50mm. Q50 Weight 20g. Solid All Metal (Aluminum & Stainless Steel) Construction