This additional lung activates when a Space Marine needs to breathe in low-oxygen or poisoned atmospheres, and even water. The natural lungs are closed off by a sphincter muscle associated with the multi-lung and the implanted organ takes over breathing operations. It has highly efficient toxin dispersal systems.

 This simplest and most self-sufficient of implants allows a Space Marine to survive his other heart being damaged or destroyed, and to survive in low oxygen environments. Not just a back-up, the secondary heart can boost the blood flow around the Marine's body

 Genetically-enhanced to be the ultimate soldiers of mankind, they are far stronger and more resilient than ordinary Human beings. Your Strength score is increased by 2

 Genetically-enhanced to be the ultimate soldiers of mankind, they are far stronger and more resilient than ordinary Human beings. Your Dexterity score increases by 2

Genetically-enhanced to be the ultimate soldiers of mankind, they are far stronger and more resilient than ordinary Human beings.  Your Constitution score increases by 2

Genetically-enhanced to be the ultimate soldiers of mankind, they are far stronger and more resilient than ordinary Human beings.  Your Intelligence score is increased by 1

Genetically-enhanced to be the ultimate soldiers of mankind, they are far stronger and more resilient than ordinary Human beings. Your Wisdom scores increase by 1

Genetically-enhanced to be the ultimate soldiers of mankind, they are far stronger and more resilient than ordinary Human beings. Your Charisma scores increase by 1

 This is essentially a pre-stomach that can neutralize otherwise poisonous or indigestible foods. No actual digestion takes place in the Preomnor, as it acts as a decontamination chamber placed before the natural stomach in the body's system and can be isolated from the rest of the digestive tract in order to contain particularly troublesome intake.

You gain proficiency in Athletics and Perception

In conjunction with the secondary heart this implant allows a Space Marine to filter his blood very quickly, rendering him immune to most poisons. 

You have advantage on sight- and sound-based Wisdom (Perception) checks (increasing your passive Perception by 5) and on checks made to identify a chemical substance.

Whenever you take damage, you ignore 1 point of damage.

 Initially implanted above the brain, this membrane eventually merges with the recipient's entire brain. Ineffective without follow-up chemical therapy and training, but with sufficient training a Space Marine can use this implant to enter a state of suspended animation, consciously or as an automatic reaction to extreme trauma, keeping the Marine alive for years, even if he has suffered otherwise mortal wounds. Only the appropriate chemical therapy or auto-suggestion can revive a Marine from this state. The longest recorded period spent in suspended animation was undertaken by Brother Silas Err of the Dark Angels, who was revived after 567 years

This organ is also known as the hibernator implant.

Implanted into the back of the brain, this pea-sized organ influences the circadian rhythms of sleep and the body's response to sleep deprivation. If deprived of sleep, the Catalepsean node cuts in. The node allows a Marine to sleep and remain awake at the same time by switching off areas of his brain sequentially. This process cannot replace sleep entirely, but increases the Marine's survivability by allowing perception of the environment while resting This means that a Space Marine needs no more than 4 hours of sleep a day, and can potentially go for 2 weeks without any sleep at all.

This implant, also called "the Remembrancer", allows a Space Marine to 'learn by eating'. It is situated in the spinal cord but is actually part of the brain. Four nerve bundles are implanted connecting the spine and the stomach wall. Able to 'read' or absorb genetic material consumed by the marine, the Omophagea transmits the gained information to the Marine's brain as a set of memories or experiences. It is the presence of this organ which has led to the various flesh-eating and blood-drinking rituals for which the Astartes are famous, as well as giving names to chapters such as the Blood Drinkers and Flesh Tearers. Over time, mutations in this implant have given some chapters unnatural craving for blood or flesh.

 A small, complex, tubular organ, the ossmodula secretes hormones that both affect the ossification of the skeleton and encourages the forming bone growths to absorb ceramic-based chemicals that are laced into the Marine's diet. This drastically alters the way a Space Marine's bones grow and develop. Two years after this implant is first put in the subject's long bones will have increased in size and strength (along with most other bones), and the rib cage will have been fused into a solid, bulletproof mass of interlocking plates.

Consists of two identical glands, implanted either into the lower lip, alongside the salivary glands or into the hard palette. The gland works in a similar way to the poison gland of venomous reptiles by synthesizing and storing deadly poison, which the Marines themselves are immune to due to the gland's presence. This allows a Space Marine to spit a blinding contact poison. The poison is also corrosive and can even burn away "strong" metals, given sufficient time

Space Marines have very organized daily routines including combat training, prayer, and indoctrination sessions with very little free time. This lends itself well to the disciplined and monastic nature of the Space Marines.