The phrase 'indispensable equipment' is correct and can be used in written English.
It is usually used when referring to something necessary or essential for a purpose or task. For example, "The firemen had to bring along their indispensable equipment in order to extinguish the flames."
The submerged combustion vaporizer (SCV) is indispensable general equipment for liquefied natural gas (LNG) receiving terminals.
Bandwidth limiting neutron choppers are indispensable key equipments for the time-of-flight neutron scattering spectrometers of China Spallation Neutron Source (CSNS).
The discharge from the home hospice is possible after the parents have been trained, family doctors informed about the child's condition, and the family provided with specialized medical equipment indispensable to the child.
In 1902, an Omega advertisement showed a wristwatch being worn by a British artillery officer, describing it as "an indispensable item of military equipment".
Walter Smith's regeneration of the Ibrox side during the 14 months since he began his second tour of duty has been unimaginably effective, his experience and astuteness complemented by the good fortune that his friend Sir Alex Ferguson insists is an indispensable part of the equipment of any successful manager.
Industrial robots and mechanized equipment have become indispensable for industrial welding for high-volume productivity because manual welding yields low production rates due to the harsh work environment and extreme physical demands (Laiping et al. 2005).
On the other hand, it brings about increased penetration of ecosystems and increased consumption of goods and services that are perceived as birdwatchers' indispensable attributes, such as optical equipment, books, travel, participation in dedicated workshops and festivals and birdwatching holidays.
For a father, we are told, is an indispensable part of one's social equipment.
In the superconducting magnet system, a widespread method of electric energy supply is realized by the current lead which is one of indispensable subsystems in the power transfer equipment; however, it causes energy losses.
