Let’s have a look at the KeyPod.
I got this one about some years ago during my first full year of OW swimming, when I just couldn’t keep putting the key in my togs… It was about twice the price of cheaper generic Aldi or otherwise units. It’s steel with a 4 number combination (the first version has 3).
Mine has been used a lot. Kicked, dropped, beaten. One evening last year Jen Hurley & I did a Sandycove double early in May. When I emerged out my brain was frozen and I was unable to remember the combination. But a sheer stroke of luck, Mick (Hurley) had taken my key off me instead. Rather than open the car and put the Keypod back in, I just locked it in place. The Keypod stood up to a half hour drive to the monthly swim meeting and another two hour drive home, all the while getting regularly clattered of the ground, all without opening. (It took about 5 hours before I could remember the code after which I changed it to sync with some other PINs).
The code is easily changed using a lever on the back once it it is open, as with most mechanical locks.
Pretty decent size , fits my car key/house key/penknife/Channel Swimmers keyring, about seven years old and still going strong. Available from Amazon.