What frames have mid-frame self-spacers?

[ugcheleuce]

Hello everyone

Can anyone here identify the frames in the image below? They have a self-spacer about halfway down the depth of the frame. What are these spacers called? Do you know of other frames that have them?



Thanks
Samuel

[BlueBee]

Hey, those are Robo spacers. ;)  I use the same thing on my Jumbo frames.  You don't want a really long surface area for the bees to propolize frames together on the big frames, hence something like this is a good replacement for the Hoffman spacers IMO.  Actually I believe Brother Adam used the idea of a simpler spacer decades ago.