Classic Connectors
Last checked: 24 August 2026
Classic K’NEX connectors join rods together to form structures. The familiar connector colours make the basic types easy to recognise, but many additional colours and specialised versions have been produced over the years.
This page brings together the known Classic K’NEX connector types, colours and part numbers, including historical and discontinued variants.
The basic connector types
The Classic K’NEX system uses a familiar sequence of connectors with different numbers and arrangements of rod connection points.
| Type | Traditional / familiar colour | Part number |
|---|---|---|
| 2-way straight | Orange | 90902 |
| 2-way | Light grey | 90903 |
| 3-way | Red | 90904 |
| 4-way | Green | 90905 |
| 5-way | Yellow | 90906 |
| 4-way 3D | Purple / Silver | 909092 / 909091 |
| 7-way 3D | Blue | 90907 |
| 8-way | White | 90908 |
The colour is useful for quick identification, but it is not sufficient on its own. Many connector types have been produced in alternative colours.
2-way straight connectors
The familiar 2-way straight connector is orange. Unlike the angled 2-way connector, its two rod connections lie opposite each other.
| Colour | Part number |
| Orange | 90902 |
| Brown | 91902 |
| Dark brown | 91902D |
| White | 909023 |
2-way straight without hole
A special version was produced without the normal central hole.
| Colour | Part number |
| Tan | 3010001 |
The tan 3010001 is therefore more than a colour variation: its construction differs from the normal 2-way straight connector.
2-way connectors (Angled)
The standard 2-way connector joins two rods at an angle.
| Colour | Part number |
| Light grey | 90903 |
| Light green | 909031 |
| Red | 909032 |
| Light grey granite | 91901 |
| Fluorescent orange | 91903 |
3-way connectors
The familiar 3-way connector is red.
| Colour | Part number |
| Red | 90904 |
| Pink | 909041 |
| Grey | 909042 |
| Fluorescent red | 91904 |
| Dark grey granite | 91909 |
4-way connectors
The traditional 4-way connector is green. A relatively large number of alternative colours have been documented.
| Colour | Part number |
| Green | 90905 |
| Black | 909052 |
| Light green | 909053 |
| Grey | 909055 |
| Mid blue | 909056 |
| Red | 909057 |
| Dark green | 90905D |
| White | 90905W |
| Fluorescent green | 91908 |
| Metallic green | 91905 |
| Yellow | 99086 |
5-way connectors
The familiar 5-way connector is yellow.
| Colour | Part number |
| Yellow | 90906 |
| Dark grey | 909062 |
| Mid blue | 909063 |
| Light green | 909064 |
| Red | 909065 |
| Light grey | 90949 |
| Light yellow | 90906L |
| Orange | 90906OR |
5-way connector for Track
The orange 90910 is a specialised 5-way connector designed for track construction.
| Type | Colour | Part number |
| 5-way for Track | Orange | 90910 |
It should not be confused with an ordinary orange 5-way connector. The specialised connector was used extensively in Classic K’NEX roller coaster construction.
4-way 3D connectors
The 4-way 3D connector differs from an ordinary flat 4-way connector. Its geometry allows construction in three dimensions and it can interlock with compatible 3D connectors.
Several colours and part-number variants are known.
| Colour | Part number | Notes |
| Purple | 90909 | old code |
| Silver | 909091 | documented later version |
| Purple | 909092 | documented version |
| Dark purple | 909092D | colour variant |
| Red | 909093 | colour variant |
| Fluorescent green | 90909FG | colour variant |
| White | 90909W | colour variant |
| Yellow | 99084 | colour variant |
Parts documentation also records Purple, Pink, Grey and White 4-way 3D connectors without a confirmed part number in the available listing.
These colours are noted here for completeness, but a part number should not be assigned until it can be independently verified.
7-way 3D connectors
The familiar 7-way 3D connector is blue. Like the 4-way 3D connector, it is designed for three-dimensional construction.
| Colour | Part number |
| Blue | 90907 |
| Lilac | 909072 |
| Light green | 909073 |
| Mid blue | 909074 |
| Black | 909075 |
| Red | 909076 |
| Dark blue | 90907B |
| White | 90907W |
| Metallic blue | 91907 |
| Yellow | 99085 |
8-way connectors
The familiar 8-way connector is white and provides eight rod connection positions around the connector.
| Colour | Part number |
| White | 90908 |
| Black | 90968 |
| Blue | 908003 |
| Orange | 908004 |
| Silver | 908005 |
| Purple | 90908P |
Special connector parts
Some parts are classified as Classic K’NEX connectors but do not fit neatly into the normal 2-way to 8-way sequence.
Co-cross ties
Co-cross ties are specialised connector parts associated particularly with track and coaster construction.
| Colour | Part number |
| Light green | 91430 |
| Black | 91431 |
| Fluorescent yellow | 91432 |
They are included on this page because they are documented as Classic K’NEX connector parts, although their function is more specialised than that of the standard connector sequence.
2D and 3D connectors
Most familiar Classic connectors form connections primarily in a flat plane. The 4-way 3D and 7-way 3D connectors are specifically designed to make three-dimensional construction easier.
Their shape allows compatible 3D connectors to interlock, creating connection points in different planes.
This distinction is structural. A 4-way connector and a 4-way 3D connector are therefore different parts, not simply different colour versions of the same connector.
Identifying a Classic connector
When identifying a connector, check several characteristics.
Number of connection points
Start by determining how many rod positions the connector provides.
Shape and orientation
A 2-way straight connector differs from an angled 2-way connector, even though both accept two rods.
2D or 3D construction
The 4-way 3D and 7-way 3D connectors have a different construction from ordinary flat connectors.
Colour
Traditional colours provide a useful visual guide, but many alternative colours have been produced.
Part number
Part numbers are especially important for distinguishing historical colours and specialised variants.
Special features
Some connectors differ functionally even when their basic shape resembles another connector. Examples include the 3010001 2-way straight without hole and 90910 5-way for Track.
Quick reference
| Type | Familiar colour | Part number |
| 2-way straight | Orange | 90902 |
| 2-way | Light grey | 90903 |
| 3-way | Red | 90904 |
| 4-way | Green | 90905 |
| 5-way | Yellow | 90906 |
| 4-way 3D | Purple / Silver | 909092 / 909091 |
| 7-way 3D | Blue | 90907 |
| 8-way | White | 90908 |
These familiar colours are a useful starting point, but they represent only part of the complete Classic K’NEX connector range.
About this overview
This page aims to document as many verified Classic K’NEX connector types, colours and part numbers as possible.
It includes current, discontinued and historical variants. A connector is not omitted simply because it is no longer manufactured or commonly sold.
K’NEX has been produced for many years, for different sets and markets. Additional uncommon or short-lived variants may therefore still exist. New variants will be added when they can be reliably identified.
Last checked: 24 August 2026
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