The BH-40 Ball Head with ARC-LR Lever Clamp from Really Right Stuff is a 17.0 oz mid-sized ball head that will support camera-lens combinations weighing up to 18 lb. Crafted from aluminum and stainless steel, the BH-40 has all of the features you'd expect from a professional-level head. An over-sized, ergonomic locking T-knob allows 45-degree tilting in all directions and a 90-degree drop-notch facilitates quick and accurate switching from the horizontal landscape position to vertical portrait orientation. A separate tension knob is provided to apply the appropriate pressure that safely corresponds to the weight of your camera. A third knob loosens and locks the panning base which is laser-engraved with markers every 2.5 degrees from 0 to 360 degrees. This version of the head has an Arca-type quick release with ARC-LR lever-release that ensures a snug fit for RRS-LOCK-equipped rails and plates. It provides adjustable tension and visual lock confirmation.