# Open Wall-Mount Transmitter, 304 MHz

**Manufacturer:** Linear  
**MPN:** `D-21A`

The Linear D-21A is a Normally Open Wall-mount Transmitter with a 2.4" width and 4.7" height. It features a normally open input circuit that operates in conjunction with an externally mounted normally open magnetic or mechanical contact.

## Specifications

| Attribute | Value |
| --- | --- |
| Brand name | Linear |
| Manufacturer name | Linear |
| Manufacturer | Linear, LINEAR LLC |
| DimensionUnit | inch |
| GraingerSku | 45NK63 |
| Extra Product Name | Open Wall-Mount Transmitter, 304 MHz |
| WeightUnit | lbs |
| countryOfOrigin | China |
| depth | 0.9 |
| extendedLead | 3 |
| height | 4.7 |
| height_Attrib | Height |
| length | 0.9 |
| length_Attrib | Depth |
| moq | 1 |
| MPN | D-21A |
| multiple | 1 |
| qtyInStock | -2 |
| SKU | G2439547 |
| tierMinQty1 | 1 |
| tierPrice1 | 47.59 |
| url | https://www.zoro.com/linear-open-wall-mount-transmitter-304-mhz-d-21a/i/G2439547/ |
| width | 2.4 |
| width_Attrib | Width |
| UPC | 693892955505 |
| EAN | 693892955505 |
| Part Number | D-21A |
| Model | D-21A |
| Product Group | BISS |
| Item | Wall-Mount Transmitter |
| Operating Frequency | 304.000 MHz |
| Powered By | 9V Battery |
| Includes | Loop Input Screw Terminals |
| Features | Slim Line Case Design |
| Width | 2.4", 1200, 2.599999997348, 2.6, 333, 50, 6.604 |
| Height | 4.7", 1.0999999988780001968503935, 1.0999999988780003, 1.1, 1800, 2.7940000000000005, 500, 75 |
| For Use With | Magnetic/Mechanical Contact |
| Depth | 0.9" |
| Country of Origin (subject to change) | China |
| ASIN | B00HHTZ6N8 |
| AdultProduct | False |
| Amount | 70.80 |
| Asin | B00HHTZ6N8 |
| Autographed | False |
| Binding | Misc. |
| Brand | Linear |
| Bullet_point | Each transmission causes the red LED indicator on the front of the transmitter to light, showing that the transmitter is sending a signal and that the battery is in good condition, Pressing the test p |
| Case | 1 |
| Cat | Industrial & Scientific |
| CatId | 16310091 |
| CatTree | 16310091, 16310161, 306506011 |
| ClassificationId | 306629011 |
| Currency | USD |
| CurrencyCode | USD |
| DisplayName | Wiring & Connecting |
| EANList | 693892955505 |
| Feature | Pressing the test pushbutton on the front of the transmitter will also cause the transmitter to send a signal |
| ItemClassification | BASE_PRODUCT |
| ItemName | Linear D-21A LLC Normally Open Wall Mount Transmitter, 2.4" Width, 4.7" Height |
| Item_name | Linear D-21A LLC Normally Open Wall Mount Transmitter, 2.4" Width, 4.7" Height |

## Distributor availability

| Distributor | SKU | Price (USD) | Qty | Stock | MOQ |
| --- | --- | --- | --- | --- | --- |
| Zoro | G2439547 | 47.59 | 1 | None | 1 |
| AmazonSC | B00HHTZ6N8 | 49.95 | 1 | None | 1 |
| absupply.net | LINEAR D-21A | 81.99 | 1 | None | 1 |

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Structured data: `/python/html6/product/500/254500000/254943500/part_--D21A---Linear--83275d71d1.json`  
Search API: https://www.dataalchemy.com/api/  
MCP server: https://www.dataalchemy.com/mcp