Cushman
Kenwood - Tempo
Atlas - Hallicrafters - Kenwood
Atlas
Atlas radio was known for simple and reliable designs. Owners talk about them as one might about the 57 Chevy they once owned.
To my knowledge all Atlas models use 22P single sided edge connected boards.
In the beginning of development it was reported that the filter board, located in the next to the last slot, could not be tuned easily. The right angle short edge connector to be added to the extender was suggested.
The photo of the extender in use in the end slot shows the filter board with clear access to the filter board trimmer caps.
One issue later arose when a 210 with the noise blanker option had a leads going to the PC120 board that were about an inch too short to allow the board to be plugged into the extender. Replacing the three leads with ones an inch longer was the answer.
Price for the extender board and 'L' connector is $25 plus $4 shipping and handling to the USA. $8 is the cost of shipping outside the USA.
Hallicrafters FPM-300
I don't know much about the FPM-300 except that this board was first requested and remains to be requested by those that stand by the Hallicrafters ham equipment.
Price for the extender board kit is $25 plus $4 shipping and handling to the USA. $8 is the cost of shipping outside the USA.
Tempo/Uniden 2020
This extender is identical to the Yaesu 18 pin board the following exceptions:
The Tempo board is single sided and about an inch longer so if you already have a Yaesu 18X2 or 18X1 give it a try first before ordering this one.
Price for the extender board kit is $25 plus $4 shipping and handling to the USA. $8 is the cost of shipping outside the USA.
Kenwood TS-900
This is the only Kenwood I know of that used edge connector board design. Board is identical to the Yaesu 18X2 extender.
Price for the extender board kit is $25 plus $4 shipping and handling to the USA. $8 is the cost of shipping outside the USA.