If the mending spell is cast on you, you can spend a Hit Die, roll it, and regain a number of hit points equal to the roll plus your Constitution modifier (minimum of 1 hit point).
In addition, your creator designed you to benefit from several spells that preserve life but that normally don't affect Constructs: cure wounds, healing word, mass cure wounds, mass healing word, and spare the dying.

You have resistance to poison damage and immunity to disease, and you have advantage on saving throws against being paralyzed or poisoned. You don't need to eat, drink, or breathe. Upon taking lightning damage, you cannot take reactions and speed is halved until the end of your next turn.

If your body is completely destroyed except both your heart and brain, you can be transferred into another vessel, be it biological or mechanical.

When you take a long rest, you spend at least 6 hours in an inactive, motionless state, instead of sleeping. In this state, you appear inert, but you remain conscious.

B4s feature a unique ability to communicate to other B4s wirelessly, but only to other B4s due to their incredibly complex systems. This allows non-verbal communication to be established to up to a maximum of four B4’s within 50 feet that is blocked by 1 foot of stone, dirt, or wood; 1 inch of metal; or a thin sheet of lead, but it doesn't have to follow a straight line and can travel freely around corners or through openings. Establishing a single link uses a bonus action. This does not require concentration, but can be disrupted by any effect that would break concentration using the concentration rules.

You get 10 modification points to mix and match for your B4 character.

• Leg alterations, 2 points, 1 leg mod allowed:
  
  • Mechanical Insect legs: Gain matched climbing speed by attaching new leg apparatuses.
  • Strong legs: Increases base speed to 35ft.
  • Tread Soles: Land obstacles such as rough terrain have no penalties to speed.
• Tough Alloy, 5 points: You gain +1 max HP per level.
• Hydro-friendly, 3 points: Grants you water safe parts to help swim. Gives you 30ft of swimming speed.
• Flight Mode, 8 points: Attaches thrusters to your back, giving you flight capabilities and 30ft of flight speed.
• Skill Module, 3 points: Allows for an additional point to a preferred skill.
• Stim ejector, 3 points: You have a launcher on your hip that can shoot out a flying medical bio stim that can fly up to 15ft to an ally. Does not work on mechanical persons such as yourself.
• Hologram Projector, 2 points: You’re able to discreetly launch a disc up to 15 feet and emit an extremely realistic hologram of yourself, (Acts as a spell/program)