The Arri LMB 4x5 basic kit is a lightweight, modular, clamp-on matte box system that can be configured to be very compact or built out with a range of accessories for use with diopters etc.
The LMB 4x5 Pro Kit offers maxmimum mounting flexibility (clamp on, 15mm LWS or 19mm studio), lens shading control and tilting to reduce ghosting from internal filter reflections. Attaching to rods is often required when using lenses unable to take the weight of clamp-on matte boxes.
A popular professional 3 stage, 4x5.65" clamp-on matte box. The Arri LMB-25 is light and compatible with a large range of lenses via removable clamp adapters.
The MMB-2 matte box from Arri is very compact and lightweight, weighing just 900 grams with the top flag. It clamps directly onto lenses with a front diameter of 80, 87, 95, 104, 110 or 114mm, or it can be attached to 15mm LWS rods.
The Chrosziel 450R2 Super Wide is a 15mm LWS matte box and features two independently rotating filter stages with filter trays for both 4x4" and 4x5.65" filters. Lenses as wide as 16mm (super 35mm) can be used with this matte box.