无源计数器
Passive counter
配合F型使用的计数器，有套管和显示屏两部分组成，无需电源，具有经济实惠、结构简单、无需电源等优点。常规型号：JS-3.
The counter used with F type has two parts, sleeve and display screen. It does not need power supply. It has the advantages of economy, simple structure and no power supply. Regular model: JS-3.
在线监测仪
Online monitor
配合T型使用的在线监测仪，需要有电源才能使用。一般配有电子显示屏。相比较而言功能较为强大，可配有通讯功能。
The on-line monitor used in conjunction with the T type requires power supply to be used. Generally equipped with electronic display. Comparatively speaking, the function is more powerful, and can be equipped with communication function.
IM过电压保护器计数器
IM overvoltage protector counter
常规型号：IM.
Regular model: IM.