Stainless steel body is for superior strength and limited harden shackle which is not easy to be cut. 

Of course we can do, it is customized service. You can contact us by email and let us know the details of your requirement. 

Firstly, the cost of iron cylinder is cheaper than brass cylinder.  Secondly, the appearance of brass cylinder looks better than iron cylinder when grey painting is done. Thirdly, the material of iron is harder than brass, so it will be a case that the keys works on iron cylinder not as smooth as on brass cylinder if some burrs inside of cylinder. 

1. Nothing meaningful to talk about on theory. Let us put it into actual production, what you can get is:  A)80 key differs for 20mm.  B) 100 key differs for 25mm. C) 200 key differs for 32mm. D) 600 key differs for 38mm. E)800 key differs for 50mm.  F) 1500 key differs fro 63mm. 

No difference on the function of security. From the aspect of production process, padlock with pin mechanism can be done by auto-machine now, production capacity gets increased and the precision of padlock is improved. 

“Paracentric” or “Universal”, which is most common profile, has the classic rounded “S” shape. 

Yes, Discus padlock can be provided with master key system. 

Firstly, The manufacturer is top 10 in padlock industry in China. Secondly, Third-part inspection involve in the quality check. Thirdly, our own packing factory double check the quality on each single product before putting into package. 

There are two ways we pack keyed alike padlock currently.  A) Same key number is packed in one carton.  For example, 70mm discus padlock is 72pcs in a carton, then you get 72pcs same key number from the carton.  B) Same key number per package (box or blister), which is min unit for a package, you can do 2pcs in same key number, 4 pcs in same key number or 6 pcs in same key number, but mixed key number for a full carton. 

The most popular one is discus padlock 70mm.