The quick coupler systems MS01, MS03, MS08, MS10, and MS21 are used on excavators and mini-excavators of various weight classes. For a digging bucket, screening bucket, ripper tooth, or other attachment to fit, the coupler must match the existing quick coupler.
In this guide, we show you the most important differences and reference measurements of common MS couplers.
What is the difference between MS01, MS03, MS08, MS10, and MS21?
The different sizes vary, among other things, by the pin diameter, the internal width of the coupler and the intended excavator weight class.
The following reference values can be used for initial determination:
| Coupler | Pin Ø (A) | Internal Width (B) | Excavator Class approx. |
|---|---|---|---|
| MS01 | 40 mm | 185 mm | 0.7–2 t |
| MS03 | 50 mm | 205 mm | 1.5–5 t |
| MS08 | 60 mm | 295 mm | 5–10 t |
| MS10 | 70 mm | 405 mm | 10–19 t |
| MS21 | 80 mm | 505 mm | 21–40 t |
The stated dimensions and weight classes are for guidance only. Before ordering, the actual dimensions and coupler shape on the existing quick coupler should be checked.
How do I measure an MS coupler?
For an initial assignment, you need two measurements:
- A – Pin Ø: Measure the diameter of the pin.
- B – Internal Width: Measure the internal width of the coupler from inner face to inner face.
You can then compare the measured values with the reference values or directly use our coupler finder.
→ Determine MS coupler with the Coupler Finder
MS01 – for small excavators and mini-excavators
The MS01 coupler is frequently used on smaller excavators and mini-excavators. As reference values, we use a pin diameter of 40 mm and an internal width of 185 mm.
The assigned excavator class is approximately 0.7 to 2 tons. However, the actual coupler and measured dimensions are decisive for compatibility.
→ View digging buckets suitable for MS01
MS03 – for mini-excavators and compact excavators
For the MS03 coupler, the reference values are 50 mm pin Ø and 205 mm internal width. It is typically assigned to an excavator class of approximately 1.5 to 5 tons.
Especially when distinguishing between MS01 and MS03, you should not rely solely on the excavator model, but measure the coupler directly.
→ View digging buckets suitable for MS03
MS08 – for medium weight class excavators
The MS08 coupler has reference values of a pin diameter of 60 mm and an internal width of 295 mm.
It is used on machines in the weight class of approximately 5 to 10 tons.
MS10 – for larger excavators
For the MS10 coupler, we use as reference values a pin diameter of 70 mm and an internal width of 405 mm.
The assigned excavator class is approximately 10 to 19 tons.
MS21 – for heavy excavators
The MS21 coupler is designed for significantly larger machines. As reference values, we use a pin diameter of 80 mm and an internal width of 505 mm.
The assigned excavator class is approximately 21 to 40 tons.
What is the difference between MS01 and MS03?
MS01 and MS03 differ primarily in their dimensions. As a reference, MS01 has a pin Ø of 40 mm and an internal width of 185 mm. For MS03, it's 50 mm pin Ø and 205 mm internal width.
An attachment with an MS01 coupler is therefore not automatically compatible with an MS03 coupler. The existing coupler should be checked before purchase.
Can I determine the coupler solely based on the excavator model?
Not reliably. Depending on the equipment, year of manufacture, or retrofitted quick coupler, different coupler systems may be installed on an excavator.
Therefore, we recommend measuring the coupler directly and additionally comparing the coupler shape.
Which attachment fits my MS coupler?
Once you have determined your coupler, you can search our shop for suitable attachments. Heinz Baumaschinen offers, among other things:
The search works even easier with our coupler finder. After a clear determination, suitable available attachments can be displayed there.
What if I am unsure between two couplers?
If your measured values cannot be clearly assigned, do not order based solely on the assumed designation. Instead, send us photos of the coupler and your measured dimensions. We are happy to help you with the assignment.
Trademark Notice: Lehnhoff is a trademark of the respective rights holder. The mentioned brand and system designations are used exclusively for identification, assignment, and description of the compatibility of coupler systems. Heinz Baumaschinen has no business connection with the trademark owner. Unless explicitly stated otherwise, the offered attachments are not original products of the mentioned brand manufacturer.
