Appaman's Mod Suit has the same thoughtful tailoring and modern, slim cut you'd find in a men's suit, but made with kids in mind.

Lined, two button jacket features a slim lapel, center vent, a chest pocket, two flap pockets, and an inside pocket. Suit Pants have an adjustable elastic inner waistband, zip fly with hook and bar tab closure, slant pockets on the sides and buttoned welt pockets on the back
Body: 80% polyester, 20% rayon; Lining: 100% polyester.
Machine wash cold on gentle with a gentle detergent and tumble dry on low.  Iron on low on the opposite side.