12 inches, or 30cm

You can google the length of a foot but this cable is about 1.2 meters long. It's great if you don't want to take your front wheel off but it's quite bulky. I didn't read the description properly and missed that it's a 10mm cable. It's too heavy to add to my commuting load so I don't use it but it's a serious cable that would probably be a good deterrent

I'd use a D lock.

No....

The loops are way to big to get under the saddle rails.

Try this instead...

I have Abus Granite D lock which I use to lock the rear wheel & frame to the bike rack. I loop the cable round the front wheel only.

Alternatively the cable will JUST about fit round both front & rear wheels then fasten each loop through the D lock shacke.. it is a TIGHT fit.

To secure my bike I use the following:

D Lock for rear wheel & frame

4 foot cable for front wheel (into D lock)

Smaller diameter super flexible wire kryptoflex cable for saddle & beam rack (into D lock)