HMAX Slimbox Pro — Recessed Mini-Split Line-Set Concealment Box (16″ × 5.5″ × 3.75″)

HMAX Slimbox Pro — Recessed Line-Set Concealment Box

The HMAX Slimbox Pro is a galvanized-steel recessed wall box that conceals mini-split refrigerant lines, drain, and control wiring inside the wall cavity for a clean, professional finish. Fits standard 16″ stud centers and mounts flush with drywall. This is the box high-end residential installers use when they don’t want visible line covers running down the wall. Ships from Cedars HVAC Miami — email us at [email protected].

What Makes the Slimbox Pro Different

Plastic line-cover kits look cheap and yellow within a year. The Slimbox Pro is bare galvanized steel — completely non-flammable, code-compliant in every jurisdiction, and hidden inside the wall so the finished install shows only the mini-split head and a small trim collar. Multiple knockouts let you route line set, condensate drain, and low-voltage control wiring through a single opening.

Specifications

• SKU: SLIMBOX-PRO
• Brand: HMAX
• Dimensions: 16″W × 5.5″H × 3.75″D
• Material: Galvanized sheet metal
• Stud spacing: Fits standard 16″ on-center framing
• Drain outlets: 5/8″ and 3/4″ knockouts
• Wire and line-set knockouts: Multiple round knockouts on all four sides
• Fire rating: Non-flammable (steel construction)
• Mounting: Flanged rim for flush drywall installation
• Sold as: Single unit

Applications

• Concealed mini-split line-set installations in new construction
• Retrofit installs where line covers are not aesthetically acceptable
• Luxury residential and hospitality installs
• Any ductless install where the customer wants zero visible refrigerant piping

HMAX Slimbox Pro — Frequently Asked Questions

Does the Slimbox fit 16″ on-center studs?
Yes. The 16-inch width fits between standard 16″ on-center wall studs with no modification.

Can I run condensate drain and line set through the same Slimbox?
Yes. The Slimbox has separate 5/8″ and 3/4″ drain knockouts plus multiple line-set knockouts, so refrigerant lines, drain, and control wiring can all route through one concealed box.

Is the Slimbox code-compliant?
Yes. All-steel construction is non-flammable and accepted by every U.S. building code for concealed mini-split line-set installations. Always verify with your local AHJ.

What’s included?
One HMAX Slimbox Pro concealment box. Cover plate and trim collar are sold separately depending on your finish. Email us at [email protected] for full kit pricing.

Why Buy Slimbox Pro from Cedars HVAC

• Ships direct from the distribution center — free shipping to all 50 states
• Contractor volume pricing on 10+ boxes — email us at [email protected]
• Direct HMAX distributor — factory-warranted
• 30-day return policy on unopened boxes

Shipping and Returns

Slimbox Pro ships from Cedars HVAC Supply, Miami, Florida. Standard handling 5–7 business days. Boxed dimensions are compact enough for standard ground shipping.