Engineering designers frequently use prototypes to gather input from stakeholders. Design guidelines recommend the use of quick and simple prototypes early and often in a design process. However, the type and quality of a prototype can influence how stakeholders perceive a new design concept and can therefore impact their responses. Additionally, different levels of experience, expertise, and preparedness for providing input to designers may lead stakeholders from different geographical or cultural settings to provide different responses, making the format of a prototype even more influential. Although design practitioners are known to intentionally align their prototyping approach with the specific design question to be answered, it is unclear the extent to which prototyping approaches should vary based on the stakeholders, context, and setting of a design project. To investigate how the format and quality of prototypes influence stakeholders' responses, we conducted a field study with various medical professionals in Ghana. We presented prototypes for a medical device in different formats to stakeholders and collected responses to the design through semi-structured interviews. We found that professional expertise, prototype format, and question type influenced the types of responses that stakeholders provided. These findings suggest that designers seeking input from stakeholders on new concepts should consider context-specific prototyping strategies, especially when designing at distance and across cultures.