4iiii Precision 3+ Shimano 105 R7100 Non-Drive Side Power Meter (Black)

The Precision 3+ gives you real power data without the cost or hassle of replacing a whole crankset — it ships pre-installed on a genuine Shimano 105 R7100 left crank arm, so fitting it is as simple as swapping your existing arm. A trio of strain gauges reads the changes in your pedal stroke output through the full rotation, a feature most left-side-only power meters skip, and the whole unit has been third-party tested to a verified ±1% accuracy.

At just 9 grams and 5.5mm thick, the sensor pod adds almost nothing to the crank and stays well clear of your frame and heel. With up to 800 hours of battery life from a single CR2032 coin cell, you're looking at maybe one battery change a year rather than a running maintenance chore.

It measures your left leg's power output and doubles it to estimate total watts — the standard, well-proven approach for single-sided power meters, and a genuinely reliable way to start training with real numbers rather than perceived effort alone.

Why You'll Like It

±1% third-party verified accuracy
Genuinely reliable numbers you can actually train and pace by, not just a rough estimate.

Up to 800 hours of battery life
A single CR2032 coin cell lasts the better part of a year of regular riding before needing a swap.

Dual ANT+ and Bluetooth connectivity
Pairs with your head unit and training app simultaneously, with no mode-switching required.

Apple Find My integration
Genuine peace of mind if your bike ever goes missing — you can track the power meter's location directly.

Who Is It For?

This suits riders on a Shimano 105 R7100 crankset who want to start training and racing with real power data, without the cost of a full power-meter crankset replacement. It's a straightforward, budget-conscious entry point into structured, power-based training.

For BOTS customers building a first power-based training plan, this is a genuinely accessible way to get accurate numbers without committing to a premium dual-sided system.

Good to Know

This is a left-side (non-drive side), single-sided power meter — it measures left-leg power and doubles it, rather than reading each leg independently. Have your BOTS mechanic confirm your existing crank arm length and bottom bracket compatibility before fitting.

Technical Specifications

• Compatibility: Shimano 105 R7100 crankset (Hollowtech II interface)
• Measurement Point: Crank arm (non-drive/left side)
• Connectivity: ANT+ and Bluetooth Smart (dual, simultaneous)
• Data Transfer: Power, cadence
• Accuracy: ±1% (third-party verified)
• Power Range: 0–4,000W
• Cadence Range: 30–170rpm
• Battery Life: Up to 800 hours (CR2032 coin cell)
• Protection Rating: IPX7
• Added Weight: 9g
• Crank Length: 170mm

Additional Information

• Country of Origin: China
• Imported By: Ensign Sports IGL
• Net Quantity: 1N