The Konig Standard Snow Tire Chains CB12 # TH01221097 that you referenced actually come with a rubber tensioner built into the chain system where the face of your 215/45-18 tire will be. This is a perfect solution for your 2017 Mazda 3.
Attached is a review video for you to check out. view full answer...
The Konig Standard Snow Tire Chains # TH01221097 actually come with some extra links that you can use for repairs.
If you don't already have repair pliers then part # TCRP3S is a good option to have as they were built for snow chains.
These chains will fit your 2018 Mazda 3 as long as you have the 215/45-18 size tires. view full answer...
The Thule The Stacker - Rooftop Multi-Kayak Carrier Item # TH830 consists of a front and a rear part. So you get 2 uprights. A quantity of 1 in this case means 1 complete system; a front and rear! I have linked a video review of this carrier for you. view full answer...
Yes! I am happy to confirm that the Curt Hitch - 1-1/4" # C11383 comes with all installation hardware included for your 2012 Mazda 3 hatchback. I went ahead and attached the hardware list from the instructional manual of the hitch. view full answer...
It certainly does, the fork block of the Swagman # S64704 Enforcer roof mount bike rack is lockable and includes 2 keys. I've put together a photo for you that shows this. I've also linked to a product demonstration video for you. view full answer...