Brandrup MKIV isotop

[Oranjeboom]

Hi just wanted to pick a few brains. I have a California 5.1 and am considering a preloved Brandrup isotop. Can anyone tell me if the front panel on the MKIV version comes off or is it sewn in.
The canvas on my California doesn't have the zip out front but I've read some versions of the isotop have a detachable front panel to allow air to be released and also there is less bulk to pack under the forward panel when the roof is down.
Thanks.

 

[Ch1pbutty]

The iso front panel unzips to make it easier to shut the roof, otherwise the air gets trapped between the isotop / bellow and will push the van bellows out towards the scissor mech.