Official Shimano Product: BL-M4100 Brake lever with a BR-MT420 Caliper.

Features:

• Fully bled hydraulic disc brake with adaptable post-style caliper
• Rear fully bled lever and caliper without adapters or rotors for customization
• Compatible with Center Lock rotor system for easy installation on Center Lock compatible hubs
• Can also use conventional 6-bolt rotors in 160 mm, 180 mm, and 203 mm sizes
• Opposed 4-piston design:
  • Reduces leading effect
  • Ensures optimal pad wear for increased braking control
• Two-piece caliper design for rigidity and durability
• Hinged clamp design for easy installation

Specification:

• Ergonomic alloy brake lever for optimum comfort and performance
• Mineral oil brake fluid:
  • Non-corrosive
  • Less hazardous than conventional hydraulic fluids
• Shim-less mounting system for quick installation and setup
• I-spec-EV compatible
• Brake lever features reach adjustment for a custom fit

Click here for compatible brake pads: Shimano D03S Resin Disc Brake Pads

Genuine, brand new, boxed Shimano product - Biketart are an official UK Shimano stockist.