JIS flange types?

[DDefoe]

Hi all,

I'm not exactly that schooled in piping (I'm a recent mech. eng. graduate), and was wondering if anyone could tell me the difference between the following two flange types:
- Slip on hub
- Slip on plain

It concerns JIS schedule piping, if this makes a difference.

 

[DDefoe]

edit: should have read "slip-on plate".

Anyhow, I have found the solution. Thank you.