# Reed switch glass capsule sizes: length and diameter by model (3.95 to 53.4 mm long, Ø1.5 to 5.4)

> How long and how wide is the glass capsule of a standard reed switch (KSK-1A66, 14 mm; GR100, 20 mm; 1A52, 21 mm)?

- Category: Electronics › Wiring & connectors
- Kind: Standard part
- Basis: Standex Electronics reed switch product guide (via Heilind): maximums as printed
- Page: https://xemstudio.com/objects/reed-switch-glass-sizes/ · JSON: https://xemstudio.com/api/geometry?object=reed-switch-glass-sizes · Plain text: https://xemstudio.com/objects/reed-switch-glass-sizes/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** Every file is drawn at true size with no tolerance added. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your process's clearance before making the part.

## Notes

- A reed switch is a pair of contacts sealed in a glass capsule; the capsule length and diameter set the sensor pocket, and the leads set the PCB or wire hole. The table is the Standex Electronics reed switch product guide (as hosted by Heilind): glass length and glass diameter are printed as maximums, lead diameter or lead section (width × thickness) as printed. Model names are the maker's part numbers, used as text only.
- Pocket and sensor-holder design: use the maximum length and diameter as the minimum space; leads are not part of the glass length. Gaps between models are real; other makers (Hamlin / Littelfuse, Coto) publish their own sizes and are not covered here.
- Not in the guide read: reed switch body names such as 'MK' or 'HE' families; sealed or moulded reed sensors (which are larger packages); glass lengths in inches. No files: a glass capsule is a cylinder (plain) and no outline beyond length and diameter is published.
- McMaster-Carr does not appear to list bare reed switches under a category the search could reach, so no McMaster link is given.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| reed switch glass capsule | length 3.95 to 53.4 and Ø1.5 to 5.4 (maximums, per model) | sensor pocket or bore (use the model's maximums) | slide | all |

## Sizes

| model | glass length, mm (max) | glass Ø, mm (max) | lead Ø or section, mm |
|---|---|---|---|
| KSK-1A04 | 3.95 | 1.5 | 0.8 × 0.15 |
| KSK-1A80 | 7 | 1.8 | 0.3 |
| GP400 | 10 | 1.9 | 0.43 |
| KSK-1A87 | 10 | 2 | 0.4 |
| KSK-1A35 | 10.5 | 2.1 | 1.2 × 0.2 |
| KSK-1A35/1 | 10.5 | 2.1 | 1.2 × 0.2 |
| KSK-1A31 | 11 | 2.2 | 0.5 |
| KSK-1A46 | 12 | 2 | 0.5 |
| GR/GP501 | 12.7 | 2.3 | 0.45 |
| KSK-1A66 | 14 | 2.2 | 0.5 |
| KSK-1A66/3 | 14 | 2.2 | 0.5 |
| KSK-1C90F | 14 | 2.54 | 0.5 |
| KSK-1C90U | 14 | 2.54 | 0.5 |
| GR/GP560 | 14.2 | 2.3 | 0.6 |
| PR560 | 14.2 | 2.3 | 0.6 |
| KSK-1A55 | 16.5 | 2.8 | 0.6 |
| KSK-1A82 | 16.5 | 2.8 | 0.6 |
| GR100 | 20 | 2.5 | 0.6 |
| NL126 | 20.3 | 2.5 | 0.7 |
| PR126 | 20.3 | 2.5 | 0.7 |
| KSK-1A53 | 20.5 | 2.8 | 0.6 |
| KSK-1A52 | 21 | 2.75 | 0.6 |
| KSK-1A85 | 21 | 2.75 | 0.6 |
| KSK-1B85 | 21 | 2.75 | 0.6 |
| KSK-1E85 | 21 | 2.75 | 0.6 |
| KSK-1C10 | 34.3 | 5.16 | 1.01 |
| KSK-1A33 | 52 | 5.4 | 0.5 |
| KSK-1A54 | 53.4 | 5.4 | 1.3 |
| KSK-1A69 | 53.4 | 5.4 | 2.49 × 0.54 |
| KSK-1A83 | 53.4 | 5.4 | 2.49 × 0.54 |

## Where the files are

- Standex Electronics (Heilind copy): [Reed switch product guide: glass length max, glass diameter max, lead diameter per model](https://development.heilind.com/cms/wp-content/uploads/2022/06/standex-electronics-reed-switches.pdf) — web — Publisher's page; dimensions are facts

## Questions

**How big is a 14 mm reed switch?**

KSK-1A66: glass 14 mm long and 2.2 mm in diameter (both maximum), 0.5 mm leads.

**How big is a 20 mm reed switch?**

GR100: glass 20.0 mm × Ø2.5 (max), 0.6 mm leads. NL126 / PR126: 20.3 × 2.5.

**What is the smallest reed switch in the guide?**

KSK-1A04: 3.95 mm × Ø1.5 with 0.8 × 0.15 mm flat leads.

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