'Slip-on' style lens caps

[Andyman]

Hi,

Does anyone know where I can get hold of a 77mm slip-on style lens cap? I have a Sigma circular polarising filter for my 17-40L but I find it quite annoying that being a slim filter it doesn’t accept the standard Canon lens cap.

I found these on a US website but there’s no sign of a 77mm version.
http://www.adorama.com/BWC70.html

http://www.adorama.com/catalog.tpl?op=itemlist&cat1=Cameras%20%26%20Lenses&cat2=Lenses&cat3=Lens%20Caps

Any advice would be much appreciated.

Best regards,
Andy.

[Dante King]

End of a paper cup. I own a restaurant so I have access to varied sizes of to go contianers. Think that this just might work.