Master Lock 40TRI Shrouded Stainless Steel Disc Padlock Pack of 3

In this review the Master Lock 40TRI shrouded stainless steel discus padlocks are evaluated for storage and outdoor security use. The pack of three keyed-alike locks is aimed at owners of storage units, sheds, trailers and garage doors who need a corrosion-resistant, cut-resistant solution that is easy to manage with one set of keys. The single biggest reason to buy is the shrouded stainless steel body combined with a hardened shackle and dual locking levers, which together prioritize mechanical resistance over low-cost convenience.

Key Features

• Shrouded body: Minimizes shackle exposure to reduce the risk of bolt cutter or shear attacks, improving cut resistance for outdoor use.
• Stainless steel construction: Provides corrosion resistance for both indoor and outdoor environments, helping the locks last in wet conditions.
• Hardened steel shackle: The 3/8 in diameter hardened shackle increases resistance to cutting and sawing compared with basic shackles.
• 4-pin cylinder and dual locking levers: Offers basic pick and pry resistance to protect against casual theft attempts.
• Keyed-alike set: Three padlocks come with two keys that open all locks, simplifying key management for multiple doors or units.
• Compact wide body: The 2-3/4 in wide body balances a low profile with a sturdy build suitable for storage doors and has clear fit dimensions to check against your hardware.

Who It's For

The Master Lock 40TRI is best for people who need reliable, low-maintenance security for storage units, sheds, trailers or garage doors and prefer keyed-alike convenience. Its stainless steel body and shrouded design make it suitable for outdoor exposure where rust resistance and physical durability matter.

Those who should look elsewhere include buyers who require high-security, patented key control systems or electronic access; this is a mechanical discus-style padlock focused on toughness and value rather than advanced key management or highest-level commercial security.

Pros & Cons

Pros

• Sturdy stainless steel body and shroud offer good corrosion resistance and physical protection.
• Hardened 3/8 in shackle and dual locking levers improve cut and pry resistance compared with basic locks.
• Keyed-alike convenience across three padlocks simplifies use for multiple doors.
• Limited lifetime warranty adds long-term peace of mind from a known brand.

Cons

• Some users report mixed fit and ease-of-opening with certain storage unit latches, so measuring backset and cross bore is important.
• Not a high-security restricted-key system, so it may not meet needs where controlled key duplication is required.

Specifications

Brand	Master Lock
Model	40TRI (pack of 3)
Body material	Stainless steel shrouded body
Shackle	Hardened steel, 3/8 in diameter, 5/8 in length
Body width	2-3/4 in
Keying	Keyed-alike, three padlocks with two keys
Locking mechanism	4-pin cylinder with dual locking levers

Our Verdict

The Master Lock 40TRI pack is a sensible value pick for homeowners and renters who need dependable mechanical security for storage units, sheds or trailers. It combines a shrouded stainless steel body and hardened shackle for tangible resistance to cutting and corrosion, and the keyed-alike set keeps key management simple, making it good value for most everyday outdoor locking needs.

Frequently Asked Questions

Are these padlocks weather resistant?
Yes, the stainless steel body is designed for indoor and outdoor use and provides corrosion resistance compared with plated or nonstainless locks.

Do the two keys open all three locks?
Yes, the three padlocks are keyed-alike so both supplied keys operate every lock in the pack.

Will this fit any storage unit latch?
Measure your door's backset, cross bore and thickness before buying; some customers note fit and ease-of-opening can vary with different latches.