I. Scenario Introduction: An Order Referred by a Returning Customer In early 2025, a municipal sanitation department in a district of Nanjing City (hereinafter referred to as 'the client') urgently needed to procure a batch of compact sewer cleaning trucks for routine desilting operations in urban drainage networks, culverts, and low-lying areas. The procurement plan explicitly specified requirements: Dongfeng double-cab chassis, blue license plate classification, tank capacity of approximately 3 cubic meters, and a budget capped at around RMB 172,000 (based on local public tender information). This was not the client’s first purchase of sanitation vehicles. As early as 2023, the client had procured four 5-cubic-meter street sweepers (model reference: CLW5070GSSD6, with related chassis) from Chengli Special Purpose Vehicle Co., Ltd. via public tender. After delivery, those vehicles operated stably, with zero failures in the superstructure and rapid after-sales service response—establishing trust in the Chengli brand. When the new sewer cleaning truck requirement arose, the client’s procurement manager directly contacted Zhang Yue, Sales Manager at Chengli Special Purpose Vehicle Co., Ltd. (Tel: ), stating clearly: 'The previous batch of street sweepers performed well—we’d like you to submit a detailed proposal for this sewer cleaning truck.' This phone call epitomizes Chengli’s reputation-driven referral model. II. Referral by a Returning Customer: The Trust Chain from Street Sweepers to Sewer Cleaning Trucks In the sanitation vehicle procurement sector, recommendations from existing users often carry more weight than any advertising. Chengli Special Purpose Vehicle Co., Ltd. has long specialized in sanitation vehicles, serving over 500 municipal sanitation departments nationwide; such 'customer-to-customer referrals' account for over 40% of its case database. For instance, the four street sweepers delivered to the Nanjing client in 2023 featured Dongfeng chassis and Chengli-manufactured superstructures, equipped with high-pressure cleaning systems and suction-sweeping units. With an average daily operating distance of ~60 km, these vehicles have demonstrated excellent performance over more than one year of operation. Client feedback included: 'Cleaning effectiveness is outstanding, failure rate is low, and spare parts arrive within two days upon a single service call.' Based on this authentic user experience, the client proactively requested quotations from Chengli when planning the sewer cleaning truck procurement—validating Chengli’s accumulated strengths in product quality and service: original Dongfeng chassis with nationwide warranty coverage, and lifetime support for the superstructure, including 24-hour direct dispatch of spare parts. This 'original-chassis + lifetime-superstructure' dual assurance maximizes reliability within the client’s budget constraints. Additionally, prior to procurement, the client consulted another local subdistrict environmental maintenance unit, which had purchased a 4-cubic-meter compression garbage truck from Chengli in 2024 (public tender reference: unit price approx. RMB 110,000–135,000). Following private discussions between procurement managers of both units, they jointly concluded that Chengli’s proposals offered superior configuration transparency and cost-effectiveness compared to competing brands. Such peer-to-peer, real-world endorsements became a decisive factor in finalizing this sewer cleaning truck order. III. Vehicle Configuration & Budget Analysis: Dongfeng Double-Cab Blue-License Sewer Cleaning Truck (3 m³) To meet the client’s requirements, Chengli Special Purpose Vehicle Co., Ltd. recommended a blue-license 3-cubic-meter sewer cleaning truck built on the Dongfeng double-cab chassis, with official announcement model number CLW5070GSSD6 (dedicated sewer cleaning superstructure). Key specifications are as follows: Item Parameter/Description Chassis Model Dongfen