General guidance from CT DRS rules, not tax advice. Confirm edge cases with DRS (860-297-5962) or your accountant.

Taxable at 6.35% (mark the line T)

• Locks, keys, cylinders, hardware, and any part sold to the customer, including shop supplies you bill for.
• Locksmith labor: installing, repairing, servicing, rekeying, and lockouts, for both residential and commercial customers and vehicles.
• Service-call and minimum charges, hourly or flat rates, mileage, and pickup or delivery charges. DRS treats all of these as locksmith service charges.
• Shipping or delivery on taxable goods.
• Repair and maintenance services to commercial, industrial, or income-producing property, and security or alarm system installation on such property.

Generally not taxed

• Sales to a customer who gives you a resale certificate (CERT-100), a qualifying exempt organization (CERT-119), or a government agency (CERT-134). Use the tax-exempt switch above and keep the certificate.
• Non-enumerated repair work on an owner-occupied home that is not locksmith work (for example general carpentry on a door). Check IP 2006(35) before treating anything as exempt.

Invoice rule

Conn. Agencies Regs. § 12-407(2)(i)(T)-1 requires locksmiths to separately state the charge for parts and the charge for services on the customer's bill. Every job here does that automatically.