This is an Eduard A-4 Skyhawk boarding ladder. I had to remove about 12mm to make it the correct height for the Skyray. Both aircraft had no built in way for their pilots to enter and required a ladder (which were almost identical in design).
The ladder attached to the jet. I am still researching on the correct color for this SQN. Most F4D SQN's had red ladders, but I have seen photos of yellow ones too.