So I got an Isofrane recently. and I wasn't happy with the fat springbars fit in them. I had to force them with oil all over them and they only stuck out a tiny bit (granted I did get the 22mm) anyways so yeah I wore it with the fat bars for a while and didn't really like the fact that there was barely anything holding on the strap.
Well I had ordered two other straps earlier and didn't think anything of the spring bars they came with. But then I thought "hey maybe they have ones that are skinny." and low and behold:
Left: Stock Seiko Fat Spring bar
Middle: watchgecko skinny thick springbars.
Right: wjean skinny spring bar
Obviously the middle one is the best of the skinny bars. It have that extra length in the ends that reaches the perfect amount for the iso.
Here's a watchgecko skinny thick springbar in the iso on the top and a seiko fat bar in an iso on the bottom. Mind you this is the 22mm isofrane but it easily squeezes into the 20mm monster lugs.
So heres the spring bar in the monster lug:
Notice how it has lots of bar sticking out of the iso to fit in the lug holes. and how the shaft thing fills most of the lug space like a good spring bar should.
And heres some pictures of the 22mm iso on the monster with watchgecko spring bars: