# H-Jamb vs. Bulb Seal: Which Shower Door Seal Do You Need? | IDEAL Shower Doors

URL: https://idealshowerdoors.com/store/guide/h-jamb-vs-bulb-seal
Description: H-jambs and bulb seals both seal the vertical edges of a glass shower door. When to use a rigid H-jamb, a soft clip-on bulb seal, or a tape-on bulb seal.
Seller: IDEAL Shower Doors, Danvers, MA (https://idealshowerdoors.com/store/)

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Guide

# H-Jamb vs. Bulb Seal: Which Shower Door Seal Do You Need?

By the [IDEAL install crew](https://idealshowerdoors.com/) · Frameless glass showers in Massachusetts and New Hampshire since 2014 · Updated 10-04-2026

Both close the gap along the vertical edge of the door. The right one depends on what the door closes against and how big the gap is.

## H-jamb

A clear rigid seal that pressure fits onto the edge of a fixed glass panel where the door closes in a straight line (180°). The door closes against it. Examples: [CRL P380HJ](https://idealshowerdoors.com/store/p/p380hj) for 3/8" glass, [CRL P120HJ](https://idealshowerdoors.com/store/p/p120hj) for 1/2".

## Bulb seal

A round, soft bulb that compresses as the door closes. It comes two ways:

- **Clip-on**, pressure fit onto the glass edge, made for one [glass thickness](https://idealshowerdoors.com/store/measure) ([CRL PCR10](https://idealshowerdoors.com/store/p/pcr10) for 3/8").
- **Tape-on**, stuck to the glass edge or wall with [VHB tape](https://idealshowerdoors.com/store/p/cat0401436) and chosen by the gap it closes, not the glass thickness ([CRL SDTB](https://idealshowerdoors.com/store/p/sdtb)).

## Which to choose

| Your door | Use |
| --- | --- |
| Closes against a glass panel in a straight line | [H-jamb](https://idealshowerdoors.com/store/c/inline-180) |
| Hinge side, or against a wall, small gap | [Bulb seal](https://idealshowerdoors.com/store/c/bulb-fin), or an 'H' wipe like [CRL P375HW](https://idealshowerdoors.com/store/p/p375hw) |
| Uneven gap or wall that isn't plumb | Soft bulb seal (it compresses to fit) |

- [Not sure which seal you need? Use our Seal Finder Pick your door, point to where it leaks and we'll show only the seals that fit your glass. Takes about 30 seconds. Start the Seal Finder →](https://idealshowerdoors.com/store/finder)

## Products in this guide

- [CRL P380HJ Clear 'H' Jamb, 180°, for 3/8" Glass 3/8" glass · 95" · 3 colors from $18.90 View](https://idealshowerdoors.com/store/p/p380hj)
- [CRL P120HJ Clear 'H' Jamb, 180°, for 1/2" Glass 1/2" glass · 95" · 2 colors from $20.48 View](https://idealshowerdoors.com/store/p/p120hj)
- [CRL PCR10 Clear Bulb Seal for 3/8" Glass 3/8" glass · 95" $29.38 View](https://idealshowerdoors.com/store/p/pcr10)
- [CRL SDTB Clear Vinyl Bulb Seal, 5/32" to 7/32" Gap 95" $26.25 / 5-pack $5.25 each · sold in packs of 5 View](https://idealshowerdoors.com/store/p/sdtb)
- [CRL P375HW Multi-Purpose 'H' Wipe for 3/8" Glass 3/8" glass · 95" $15.23 View](https://idealshowerdoors.com/store/p/p375hw)

## Common questions

**What is an H-jamb on a shower door?**

A clear rigid seal that fits on the edge of a fixed glass panel where the door closes in a straight line. The door closes against it.

**When should I use a bulb seal on a shower door?**

On the hinge side or where the door meets a wall, especially if the gap is uneven: the soft bulb compresses to close it.

## More guides

[**Sweep vs. drip rail** They do two different jobs at the bottom of the door, and the most popular frameless bottom seals combine both in one piece..](https://idealshowerdoors.com/store/guide/shower-door-sweep-vs-drip-rail)[**33S vs. RTV408 silicone** Both are 100% silicone.](https://idealshowerdoors.com/store/guide/acetic-vs-neutral-cure-silicone-33s-vs-rtv408)[**Clear vs. black seals** Clear and black versions of the same seal fit and work exactly the same.](https://idealshowerdoors.com/store/guide/clear-vs-black-shower-door-seals)[**Shower door leaking at the bottom** Water on the bathroom floor almost always comes from one of four places.](https://idealshowerdoors.com/store/guide/shower-door-leaking-at-bottom)