Mason 300 - SEATYLOCK


Mason 300

The Widest of its kind! PATENTED pentagonal hardened steel crossbar profile - Stronger than any rounded crossbars, Double deadbolt locking mechanism for protection against twist attacks. *Mounting Bracket sold separately  

    Customer Reviews

    Based on 4 reviews
    Benjamin Koltai
    Great D-lock for Aventon Aventure

    I recently purchased an Aventon Aventure e-bike for daily commuting, and use a Mason 300 D-lock in combination with Kohlburg Alcatraz 5' 13mm chain lock for two SS diamond-rated layers of security. The geometry of Aventon Aventure requires a large D-lock to fit through the frame, fat tires, and a bike rack, and the Mason 300 works great, meeting both length and width requirements to provide multiple locking alternatives. The extra $12 for the lock mount is totally worth it, and I attached mine to the front fork. Mason 300 is a winner.

    Olga Radushkevich
    A very good lock!

    I use it for my e_bike, feel very safe with this lock! It is big and wide! I have attached it to my front fork for carrying around with the additional attachment system, and it's working really well! Thank you!

    Works Great

    The lock is big and a little bulky, but I can lock my folding bike to a pole while it's folded.

    Awesome Lock

    I recently purchased 2 fat tire e bikes for my wife and I. It was a pain trying to find a lock that would work with them given the 4inch fat tires. After days of research (countless YouTube videos) I came across the Mason 300 lock. I really liked the design and the fact that it had a diamond bike rating from sold secure. Coupled with the fact that I could mount the locks to our front forks, I pulled the trigger and bought two. They both arrived quickly and very well packaged. They work perfectly on our fat tire bikes in locking the tire and frame to bike racks. I purchased two mounts and have them installed on our front forks to store the locks when we're not using them. Highly recommend these locks. Especially since they are the biggest diamond bike rated u locks I could find that would work on our bikes.

    Stay in the Loop!

    🚨 Attention all cyclists! 🚨

    Unlock exclusive deals, insider news, and pedal-worthy updates! Sign up for our newsletter to join the ride.