LEGO® Arch 1 x 5 x 4 is a blue architectural part with a large curved opening, stepped outer sides, and MPN 30099.
LEGO® 1 x 5 x 4 Arch Part
This arch piece creates a tall curved opening while keeping a squared outer profile for surrounding wall sections. The stepped side shape gives the part a strong architectural look without needing several smaller pieces to form the same curve.
Useful Shape for Entrances and Curved Structures
Large 1 x 5 x 4 arch format
Curved inner opening for doorways, windows, and structural details
Stepped outer profile for layered walls and raised sections
Side and underside connection points visible for stable placement
