Compensating cables consist of twisted cores and are identified by a color code and code letters as follows:
Letter 1: code letter for the
thermocouple
Letter 2:
X: same material as
thermocouple
C: special material
Letter 3: several types of compensating cable can be distinguished by a third letter.
Example:
KX:
compensating cable for NiCr-Ni thermocouple Type K made from thermocouple material
RCA:
compensating cable for PtRh-Pt thermocouple Type R, made from special material Type A
The tolerance classes 1 and 2 are defined for compensating cables.
Class 1 has closer tolerances, which can only be met by extension cables made from the same material as the thermocouple, i.e. the X-type.
Compensating cables **proper are normally supplied to Class 2.

Не совсем понимаю, почему здесь proper стоит не впереди существительного (как определение), а после него..

Спасибо.