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Master Lock 8170D, 6-1/8 inch Wide U-Lock with 8" Shackle, Black

  • Based on 5,049 reviews
Condition: New
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Availability: In Stock.
Fulfilled by Amazon

Arrives Thursday, Sep 17
Order within 20 hours and 52 minutes
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Size: 6-1/8 inch U-Lock


Style: No Cable


Features

  • Outdoor heavy duty bike U-lock is best used as a bicycle lock.Note: Measure your door's backset, cross bore and thickness to ensure you find the right fit.
  • U-shaped steel bike lock with key; Includes carrier bracket for easy transportation
  • Bike lock features a hardened steel body and double locking shackle for superior cutting and prying resistance
  • Bike lock body is 6-1/8 in. (16 cm) wide, with 8 in. (20 cm) shackle length, 4 in. (10 cm) width and 1/2 in. (13 mm) diameter
  • Includes one u-lock bike lock, two keys

Description

The Master Lock U-Lock is engineered for those who value their ride. This bicycle lock offers unparalleled security to ensure your bike stays right where you left it. It is crafted from hardened steel that can withstand significant impacts and resist all manner of attempts at tampering or cutting. This makes it an exceptional choice among bike locks for anyone serious about anti-theft security. The bike lock body is 6-1/8-inches wide with an 8-inch shackle length. Whether you are locking up your bicycle in a bustling urban environment or a quieter suburban area, trust that this heavy-duty bike lock has you covered. Its imposing presence alone deters would-be thieves before they even think about attempting anything nefarious. But what sets this U-lock bike apart from others? The answer lies in its intuitive design and ease of use. Despite its strength and durability, the Master Lock 8170D U-Lock is incredibly user-friendly. It boasts a double-locking mechanism providing twice the security while ensuring quick access when you need to unlock it swiftly. Lightweight yet sturdy, this U-lock fits easily into most backpacks or bike accessory bags without weighing you down. Investing in the Master Lock U-Lock means investing in long-term security for your precious ride. Unlock superior protection now with Master Lock: where studied design meets impenetrable strength.

Brand: Master Lock


Special Feature: Heavy Duty


Lock Type: Key Lock


Item dimensions L x W x H: 9.8 x 7.33 x 1.33 inches


Material: Alloy Steel, Rubber


Brand Name: Master Lock


Recommended Uses For Product: Bike


Number of Pieces: 1


Included Components: U-lock bike lock, two keys, and a carrier bracket


Model Number: 8170D


UPC: 071649222771


Model Name: 8170D


Global Trade Identification Number: 71


Manufacturer Warranty Description: Limited Lifetime Warranty


Number of Items: 1


Manufacturer: Master Lock


Number of Packs: 1


Unit Count: 1 Count


Item Type Name: U Lock


Manufacturer Part Number: 8170D


Additional Features: Heavy Duty


Lock Type: Key Lock


Controller Type: Hand Control


Control Method: Touch


Style Name: No Cable


Color: Black


Shape: U Shape


Material Type: Alloy Steel, Rubber


Finish Types: Vinyl Coating


Item Dimensions: 9.8 x 7.33 x 1.33 inches


Item Weight: 2 pounds


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Thursday, Sep 17

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Leasing options through Acima may also be available during checkout.

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Top Amazon Reviews


  • Strong, Secure, and Useful for More Than Just Bikes
Size: 7-1/4 inch U-Lock Style: Lock
I originally chose this U-lock for a bicycle, but I ended up using it to secure the door on our outdoor shed, and it has worked extremely well. The lock feels very sturdy and well made. It’s easy to lock and unlock with the included keys, and the solid construction gives me confidence that it’s helping keep our belongings secure. I also appreciate that the protective coating helps prevent scratches. Even though it’s marketed as a bike lock, I found it to be a versatile security lock that works well for other outdoor applications too. If you need a dependable lock for a bicycle, shed, gate, or similar item, this is a great option. Overall, it’s a quality Master Lock product that’s simple to use, durable, and provides excellent peace of mind. ... show more
Reviewed in the United States on June 26, 2026 by Jenny’s Cozy Corner

  • A good deal; I'd buy them again!
Size: 7-1/4 inch U-Lock Style: Lock
The deal I had on Amazon was hard to pass on, and I've been looking at this product for a while. Point, click, wait... they arrived in a sturdy box, in impeccable condition. One word of warning... the key releases the bar completely from the horseshoe section, so it will drop off once it is disengaged. No regrets; I'd buy them again ... show more
Reviewed in the United States on July 15, 2026 by o2btravling

  • Ole skool Master bike lock outstanding
Size: 7-1/4 inch U-Lock Style: Lock
The best bike lock on the market not only secure but turn thieves away instantly on sight
Reviewed in the United States on July 23, 2026 by Rashard

  • Decent enough.
Size: 7-1/4 inch U-Lock Style: Lock
Good deterrence thick enough outside the most determined. Only issue is the ubar comes out completely. Slower for unlocking applying and locking.
Reviewed in the United States on July 28, 2026 by Dagon

  • Very effective!
Size: 7-1/4 inch U-Lock Style: Lock
This lock saved my scooter from getting stolen! It was bent out of shape but never broke! It had to be cut off so I am ordering a replacement now! I highly recommend!
Reviewed in the United States on June 9, 2026 by Amazon Customer

  • Id trust it
Size: 7-1/4 inch U-Lock Style: Lock
Awesome lock! trusted in a crazy neighborhood and fairly priced would recommend
Reviewed in the United States on July 29, 2026 by Andrew Fortenberry

  • Nice lock
Size: 7-1/4 inch U-Lock Style: Lock
Nice lock for me
Reviewed in the United States on August 25, 2026 by Yuhaoyeh

  • Beautiful
Size: 7-1/4 inch U-Lock Style: Lock
Super high-quality Master lock; I like it because it keeps my scooter secure.
Reviewed in the United States on July 31, 2026 by CarlaMachado

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