Why the main body length and maximum length with a rear attachment should be recorded separately.
Use two measurements when they answer different questions
Yes. If a rear attachment projects beyond the main body, a clear specification should normally distinguish the body length from the maximum overall length including that attachment. The first value helps readers understand the principal product form; the second describes the full space the assembled item occupies. Combining them under an unexplained length label hides an important difference.
Define the configuration and endpoints
Each value should name its endpoints and the product state in which it was measured. The record should also say whether the rear component is fixed, supplied as an option, or present only in a particular configuration. If its status has not been documented, do not assume it is removable merely because it appears visually separate.
The maximum dimension must include the farthest projecting point of the attachment. Ignoring a protrusion can undermine storage or clearance comparisons. Conversely, presenting only the maximum length can make the main body seem longer than it is. Reporting both values avoids forcing one number to serve two different purposes.
Keep comparison conditions consistent
Measurements being compared should use the same unit, orientation, state, and endpoint convention. Small differences can also arise from resolution, rounding, or the measurement method, so the method should be retained with the value whenever it is available. NIST Technical Note 1297 provides general guidance on evaluating and expressing measurement uncertainty; it does not establish any dimension for a particular product.
Until the attachment structure and measurement basis are confirmed for an exact model, label the values descriptively rather than presenting an inferred number. A concise specification might separate body length, overall length with attachment, and attachment status. That format tells readers both what was measured and which physical configuration the number represents.