Part# 11-00745
MFR Model# P1-12121
MIL No.Otto No.DescriptionPart Number
MS25089-1ALP1-12121Press Fit, Red11-00745


The P1 is a sealed, dustproof, snap action, military grade switch ideal for switching low level up to 10 amps. It features screw terminals, and includes screws, lockwashers, and solder lugs. MIL qualified. Dustproof, snap action, screw terminals, rugged reliable construction.

Electrical: (at 28VDC or 115VAC, 60/400 Hz.)
Load Amperes Life (Nominal)
Resistive 10 25,000 cycles
Inductive/Motor 5 25,000 cycles
Lamp 3 25,000 cycles
California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm -


  • Button sealed with patented “rolling sleeve” principle
  • Contact area sealed at button & terminals
  • Less than 25mΩ contact resistance
  • Ideal for low level switching as well as up to 10 amp duty
  • Positive tactile feedback


I havent used the button yet, but it appears and feels very high quality, button has great snap action. The button was shipped quickly and packaged well. I would and plan to purchase more of these buttons.

Christopher G Verified Purchase


March 30, 2022

Switch is excellent quality, but I decided 4 lb force was too high after trying it. I subsequently bought a 2.5 lb force version from another source since you dont offer it. Its much better as a GA PTT.

October 29, 2020

Excellent quality. Love that there is positive feedback when switch is pushed. It requires a bit more push than the old switch, but not bothersome. Wish the attachment had slightly larger screws and connectors. Instead, we soldered the wires to the two terminals.

September 23, 2020

LOVE em! Perfect feel for a com PTT switch.

David N
April 23, 2020

This PTT is really high quality but way too large to install without modifying a standard yoke. I really wish this company would stock normal-sized PTTs. I know some planes are setup, but just beware that this will not fit a standard PA28/172 yoke. Spruce removed the old PTTs so now all that are left are these and sub-micro ones...

January 5, 2020

Bought for my Rans s9 Chaos and seems to work as advertised.

Mark C
November 14, 2019

Perfect PTT switch for my application. Just the right pressure to activate & a positive feel engagement.

September 14, 2019

I decided to try these in my PA-38 because I use it for training and my students wear out other PTT switches quickly. They fit nicely and so far are working very well. They feel very solid and durable. The 4lb. pressure works out great since students tend to push hard on the switches.

Fly-rwi L
February 12, 2019

Bought the switch when chasing a problem that turned out to be a bad wire not a faulty switch. But I like the feel of this one with the positive click and the larger style.

November 6, 2018

Product was what expected. One good reason I use Aircraft Spruce is the website is user friendly .

Lee B
July 23, 2018


Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: For part number 11-00745 what is the diameter size of the button press fit body and is the whole item red or just the actual button?

The diameter size of the button press fit body is 9/16"(.562") and the button is red while the body is black.

Q: What does momentary mean? What does press fit mean? What does SPDT mean?

Momentary means you have to hold the switch down to activate it. As soon as you release the switch it turns off. Press fit means that there are no threads and simply pushes into an exact size hole. SPDT means single pole double throw. This is a switch that only has a single input and can connect to and switch between 2 outputs.

Q: Are the two P1 switch terminal posts (or terminal flanges) marked ground & positive?Im not very knowledgeable about these matters. By the way, 1/2 was too small, I drilled a 9/16 into my airplane control yoke & wrapped a piece of scotch tape around the cylinder and the switch fit perfectly and tightly.

No, this switch can be wired in either direction.

Q: For example, otto no. P1-12121 (spruce pn 11-00745) - according to the spec. sheet the first 2 to the right of the hyphen indicates a screw connection not a solder connection, yet your description for all these switches says they have solder connections. The otto no of this switch with a solder connection should be P1-11121. Please confirm whether 11-00745 has a solder or screw connection?

The switch has screw terminals. Included with the switch are screws, lockwashers, and solder lugs.

Q: Any reason why this shouldnt work with a 14V system?

No, this should work fine in a 14 volt system.

Q: What size mounting hole does the P1-12122 require?

.625 minimum.

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