Mid Kit for Blackmagic URSA Cine LF is an accessory kit that includes:

Top Plate (Blackmagic URSA Cine LF)
Provides 1/4-20 and 3/8-16 threaded holes with ARRI accessory pins, M4x20mm ARRI standard threaded holes, and ventilation holes for the URSA fan.  Also works on the URSA Cine Immersive Camera. 

Rainbow Handle Kit (Black)
Rainbow Handle Kit is a modular handle system that can be configured in a variety of ways, including down behind the battery, commonly referred to as a Hollywood or Panavision-style handle. Multi-Function Rod Bracket (MFRB 15mm LW) is included in the kit and has lightweight spaced 15mm rod openings which run front to back, and a sideways 15mm rod opening allows users to attach viewfinder mounts or microphone shockmounts.  Different colored grips also available.

2x Cage NATO Side Arm (ARRI 3/8-16, 135mm)
Attaches to the sides of the Top Plate and provides an ARRI Rosette adjustable NATO accessory rail with safety pins on each end.

Baseline 15mm LW (Blackmagic URSA Cine LF)
Quick-release 15mm LW baseplate with ARCA Swiss camera dovetail interface on top and ARRI standard dovetail interface on the bottom. Also works on the URSA Cine Immersive Camera.

2x 15mm Rod (9 inch)
Stainless steel iris rods.