77GH64M M-size glass gobo holder for ETC Source 4 Junior
A Rosco M-size glass gobo holder made for ETC Source 4 Junior profiles. It holds an M-size glass gobo and slides into the fixture’s gobo gate so the pattern sits at the focal plane and projects sharply.
Image: Rosco
Holds the pattern exactly where the lens needs it
A profile spot projects whatever sits in its gate. The holder keeps the gobo flat, centred and at the focal plane, so the image focuses cleanly — and lets you change patterns without handling the gobo inside a hot fixture.
- Holds one M-size glass gobo securely in the gate
- Made to fit ETC Source 4 Junior
- Retains the glass so it can’t drop out of the fixture
- Lets you swap glass gobos quickly between scenes or shows
Pattern projection on stage, set and site
Theatre & dance
Breakups, windows, foliage and texture from ETC Source 4 Junior rigs — load a gobo, focus, done.
Events & corporate
Logo, monogram and pattern projection on walls, floors and stage sets.
Film, TV & photography
Hard-edged shadow patterns such as blinds, windows and leaves on set or in the studio.
What it is — and what it isn’t
Use it for
- Loading an M-size glass gobo into ETC Source 4 Junior
- Keeping spare holders pre-loaded for quick pattern changes
- Theatre, events, film and architectural projection
- Rosco standard and custom glass gobos for this fixture
Don’t use it for
- Gobos that don’t match the holder’s size — check the glass diameter first
- Fixtures not listed — gate designs differ between makers and models
- Chipped or cracked glass — replace it rather than loading it
- Moving-light gobo wheels — those use their own fixture-specific gobos
Loading the holder
- Switch off the fixture and let it cool — the gate area runs hot.
- Handle the glass gobo by its edges (clean gloves are best), check the orientation notes supplied with it, and seat it in the holder.
- Slide the holder fully into the gobo slot/gate on the fixture.
- Switch on and focus the fixture until the pattern edge is sharp.
- Text or logos read wrong? The lens inverts the image — flip or rotate the gobo in the holder and re-check.
Key details
| Brand | Rosco |
|---|---|
| Part number | 77GH64M |
| Holder size | M-size (glass) |
| Rosco M steel gobo size (reference) | 66 mm outside diameter, approx. 48 mm maximum image area |
| Holder type | Glass — for glass gobos |
| Fits | ETC Source 4 Junior profiles |
| Supplied | Holder only — gobo sold separately |
Common questions
Which holder do I need for glass gobos in a Source 4 Junior?
This one — 77GH64M is the M-size glass holder for the Source 4 Junior. For steel gobos in the Junior, use 77GH63M.
What does a gobo holder do?
It holds the gobo (a patterned steel or glass disc) and slides into the gobo gate of a profile/ellipsoidal spot so the pattern sits at the focal point of the lens. Focusing the fixture then gives a sharp projected image.
What’s the difference between a metal and a glass gobo holder?
Metal holders are made for thin steel gobos. Glass gobos are thicker and fragile, so they need a glass holder built to retain them safely. Pick the holder to match both your fixture and your gobo type.
What size gobo does this holder take?
M-size glass. Glass gobo diameters don’t always match the steel size of the same letter, so when ordering a glass gobo, specify this fixture and holder so it’s made to fit.
Is a gobo included?
No — this is the holder only. Choose a Rosco standard gobo in the matching size and type, or order a custom gobo through CFATS.
Holder-to-fixture compatibility is taken from Rosco’s gobo holder chart. Gate designs can change between fixture generations, so check your fixture model and gobo size before ordering, and test-fit before the show. Sizes and compatibility on this page are a guide only.
Not sure which holder fits?
Send us your fixture make and model and we’ll confirm the right Rosco holder and gobo size before you order.
Gobo holder guides
