A womb nest incubator consists of an inner capsule into which the male and female eggs are placed. The capsule is transparent to allow visual inspection of the nest's exterior. The capsule sits atop a suspension system to cushion the womb nest against sudden movements. The capsule and suspension are encased in a ruggedized outer chassis that also contains a number of other components.

Chief among these is a redundant power supply, accepting both external power and a backup power source, likely a star lantern. There is a two-step air filtration system. The first step processes air going from the environment to the chassis interior, and the second step filters this air in turn before venting it into the inner capsule. Waste gases exchanged by the nest's vascularized dermis are expelled into the chassis and subject to monitoring by the incubator. Medicine and vaccines are typically delivered via aerosol through the ventilation system.

When the dermis is fully developed, a cannula is connected from the nest's interior cavity to a port on the inner capsule. This allows exploratory inspection and prenatal surgery by a healer piloting a micro mech. There is traditionally one such inspection shortly before the kits are yeaned, and it is here where in many cultures kits receive their names. At this point their coats are developed, and they are near or at their birth weight. Names are often given based on their behavior in utero during this inspection. Some may be more alert than others, responding to the pill-sized mote of light outside their amniotic sac by turning their head or reaching out with a paw*. Kits that respond this way are traditionally thought to be destined for holiness.

In addition to the expected systems monitoring the vital signs of the developing kits and the womb nest itself, there are environmental sensors to detect ambient temperature and air pressure. If the ambient pressure drops suddenly, for example due to a hull breach on an orbital colony, the exterior ventilation will be sealed and the air supplied to the inner capsule will divert to an on-board emergency supply.

The outer chassis is famously sturdy. It is shielded against radiation and hard vacuum (again to accommodate spacers) and can withstand the crushing pressures of the deep ocean (to accommodate Sweetwater's benthic cities.) It can even withstand small arms fire.

The reason why incubators are built to withstand everything short of quasiluminal munitions has to do with paternal instinct. The incubator is usually kept in the home and monitored remotely by a healer. During the kits' gestation, the sires are compelled by instinct to protect their nest, to the point of forgetting to eat. Their only waking thought is “THESE ARE THE ONLY CHILDREN I WILL EVER HAVE; I MUST PROTECT MY BABIES!”

Sires will respond aggressively to other males approaching their nest, which is one of the reasons why the medical profession is dominated by women. Women who are not part of the childermoot can examine the nest without getting eviscerated at the claws of up to six overprotective fathers. This aggression is at its height when a sire is in close proximity to his nest, but he will remain more or less irascible throughout his kits' gestation, to the point that paternity leave is legally mandated in most jurisdictions.

*This is a tentative retcon, as I previously said the kits are born blind.

Addendum:

Since yinrih only have one litter in their lifetime, incubators are rarely purchased outright. Small communities such as a lighthouse may have incubators that they loan to expecting childermoots, or they may be rented or loaned by a healthcare organization, private company, or government entity.

The inner capsule is discarded after use, and the chassis is cleaned and inspected between uses.

After yeaning, the empty womb nest may be disposed of, or the stem cells or blood within may be harvested in case of future need by one or more of the pups. In certain atavist communities the nest is eaten by the childermoot or just the sires (who haven't been eating properly the last five months), mimicking a behavior seen in tree dwellers.

The incubator also serves as a crib analog for the first few weeks of the kits' lives when they're not mobile. Once they start moving the incubator is returned.