In Theisen v. County of Los Angeles (1960) 54 Cal.2d 170, Theisen won a contract to construct a fire combat training center for the county. Theisen contracted with Petterson Corporation to supply 64 custom doors for the center. Petterson then contracted with Durand to supply 20 of the doors. Durand complied with the contract and shipped the doors to Petterson. Theisen took delivery of the 64 doors at Petterson's plant and paid Petterson in full. Petterson defaulted in payment to Durand. The Supreme Court concluded Petterson was a subcontractor and Durand, who furnished 20 of the custom doors to the subcontractor, was entitled to invoke the stop notice procedure. The Supreme Court stated: "In our opinion the essential feature which constitutes one a subcontractor rather than a materialman is that in the course of performance of the prime contract he constructs a definite, substantial part of the work of improvement in accord with the plans and specifications of such contract, not that he enters upon the job site and does the construction there. We are not here concerned with the mere furnishing of materials from which doors were to be constructed by the general contractor nor are we interested in the sale of standard stock-in-trade doors. Specifically we are dealing with a contract whereby the doors were to be fabricated according to the specifications of the prime contract and as a constituent part of the construction of the public improvement which was the subject of the contract. . . . Rather, we conclude that one who agrees with the prime contractor to perform a substantial specified portion of the work of construction which is the subject of the general contract in accord with the plans and specifications by which the prime contractor is bound has 'charge of the construction' of that part of the work of improvement and is a subcontractor although he does not undertake to himself incorporate such portion of the projected structure into the building." ( Theisen v. County of Los Angeles, supra, 54 Cal.2d at p. 183.)