IntroductionMagnetic materials are classified as hard or soft. Soft magnetic material is easy to magnetize/demagnetize, while hard magnetic materials retain their magnetic properties after being magnetized. Permanent magnets are made of hard magnetic materials capable of creating their own persistent magnetic field once magnetized. They can be manufactured in different sizes and strengths, making them implantable in the body without anatomical restrictions. Different types of magnets are used in medical applications today, from retention magnets to guides for catheters in brain surgery. Due to the increasing development of permanent magnets, more and more magnetic materials are used in medical applications. These reports will focus on medical devices such as cardiac rhythm management devices (CRMDs): implantable pacemakers, cardio defibrillators and bone distraction. These applications use activation magnets contained in a medical device which is then implanted in the human body. When the medical device is exposed to an external magnetic field, it activates or deactivates the device. Since the magnetic material is used inside the body, it must be capable of effecting an appropriate response in the host in the given application. This is often achieved through encapsulation of the magnetic material to stop any interference of the magnet with the body, which also eliminates the risk of corrosion1. Implantable PacemakerAn implantable pacemaker is used to assist the normal rate of contraction of the heart when generated by the heart. electrical impulses are impaired, which is caused by heart block – delay or absence of conduction between the atria and the ventricle. ]5) RedRock (2013) MEMS-based magnetic reed switch technology. [Online] Coto Technology [Accessed April 18, 2014]6) Reed Switch Development Corp (2013) What is a Reed Switch? [Online] Available at: http://www.reedswitchdevelopments.com/what-is-a-reed-switch.html [Accessed: April 20, 2014]7) David Prutchi. (2012) Cool Reed Switch Manufacturing [ONLINE]. Available at: http://www.implantable-device.com/2012/03/16/cool-reed-switch-manufacturing-video/ [Accessed April 18, 2014]8) Total Magnetic Solutions (2000) Alcino Magnets. [Online] Available at: http://www.magnetsales.com/alnico/Al1.htm [Accessed April 22, 2014]9) Advanced Magnetic Materials (2013) Types of Magnetic Materials. [Online] Available at: http://www.rare-earth-magnets.com/t-types-of-magnets.aspx [Accessed April 22 2014]