Set Details
- Set Number
- 7721
- Name
- Combat Crawler X2
- Theme
- Exo-Force
- Year
- 2007
- Pieces
- 581
- Complexity
- Substantial
- Build Time
- 2-4 hours
- Ages
- 10+
- Type
- Play-focused
About LEGO Combat Crawler X2
LEGO Combat Crawler X2 (set #7721) is a large, detailed build with 581 pieces from the Exo-Force theme, released in 2007. The Exo-Force line features anime-inspired mech battle robots. At 581 pieces, this is a substantial-level build with an estimated build time of 2-4 hours, suitable for ages 10+.
Set Highlights
- 581 pieces at substantial complexity — a 2-4 hours build.
- Compatible with all standard LEGO sets — bricks extend naturally into other sets you own.
- Play-focused build with interactive elements designed for 10+ builders.
Who Is This Set For?
Gift for Ages 10+
The substantial difficulty makes this accessible without being trivial — a well-matched gift for LEGO fans in the 10+ age range.
Weekend Build Project
581 pieces with an estimated 2-4 hours fits comfortably into a focused afternoon or weekend session.
Expanding a Exo-Force Collection
A solid addition for collectors building out their Exo-Force shelf. Introduces parts and builds that complement other sets from the same line.
Build Tips
A five-minute sort by color or piece type before starting saves time hunting for specific bricks mid-step.
Follow the numbered steps in sequence — structural elements early in the build support everything that comes after.
For active play sets, key connection points (hinges, turntables, clip joints) can loosen over time — a small dab of LEGO's own tube clutch lubricant on the stud resolves most looseness without damage.
Finding Instructions
Building instructions for LEGO Combat Crawler X2 (#7721) are available as a free PDF on LEGO.com. You can also upload a photo of this set to LegoFinder to identify it and access the instructions directly.
Combat Crawler X2 FAQ
Related Reading
More Exo-Force Sets
See all Exo-Force →
![LEGO Golden Guardian [Limited Gold Edition]](https://cdn.rebrickable.com/media/sets/7714-1.jpg)
Also Released in 2007
All 2007 sets →Similar Build Difficulty
Sets at roughly the same piece count and complexity tier — different theme and year, but a similar build experience.
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