Oppo A18 and A38 hard back covers are typically crafted from durable, impact-resistant polycarbonate (PC). They feature precise cutouts for buttons and ports, a raised bezel around the camera bump for lens protection, and a sleek matte or glossy finish that ensures a comfortable, anti-slip grip without adding bulk.

Hard back covers for the Oppo A18 and Oppo A38 measure approximately 16.4 x 7.5 x 0.8 cm (6.45 x 2.95 x 0.3 inches). Because both phones share identical physical chassis dimensions (163.7 x 75.0 x 8.16 mm), their cases and covers are completely interchangeable