Rating and pole count are the item
An MCB is defined by its current rating, its pole count, its breaking capacity and its curve, and each combination is a different product at a different price. Entering them as one item called MCB makes stock useless and rate errors constant. Each as its own item with a searchable code is what lets the counter confirm from the screen rather than from a box on a shelf.
Panels are assembled, not sold off the shelf
A distribution board is an enclosure plus a set of breakers, busbar and accessories, assembled to a requirement. Quoting that as one figure hides both what went in and your margin on assembly. Building it as a quotation with the components listed, converting to an invoice when approved, means the customer sees the specification and you have a record of exactly what was supplied when a fault is reported.
Contractor accounts across jobs
Electrical contractors draw switchgear through a wiring job that will be paid at the end, so material goes out over weeks against work that has not been billed. A credit limit set at the start stops a stalled job continuing to draw, ageing shows which jobs have slipped, and a monthly statement settles the account while the work is still fresh for both sides.
Warranty and brand traceability
Switchgear carries manufacturer warranties and a failed breaker is a claim. Recording brand, model and rating on the invoice means the claim is traceable and honoured rather than absorbed. It also means that when a contractor reports a nuisance trip you can see exactly which product went to that site and whether others had the same issue.