Tulsi mala

image released into the public domain by author Madhavi Madhurakavi. Tulsi Mala.

Japa is the Hindu word for repetition of the Lord's name and mala means a chain.There are different kinds of japmalas (Rosary or prayer beads )which are used for different Gods and mantras.A Vishnu devotee generally uses a mala where the beads are carved out from the stem of the Thulsi aka Holy basil plant.
Wearing a Tulsi mala is supposed to be extremely beneficial for the mind,body and soul.It makes a person healthier in body ,calmer in mind and sinless in spirit.
The malas used for wearing are generally much smaller and smoother in finish.There are many varied opinions about the code of conduct to be maintained by a person while wearing them.Interested seekers may adhere to what they believe in.
For another tip to reduce the effects of cell phone radiations with tulsi beads you may refer:

http://simpleayurvedichealthtips.blogspot.in/2010/10/some-ways-to-protect-ourselves-from.html

Some ways to protect ourselves from Cell phone radiation and the other radiation dangers

The RF  and electromagnetic waves from various sources these days especially the cell phone towers and mobile phones are very dangerous for plants and animals and also hazardous to humans.

      A few tips as recommended by Panditha Elchuri are given below:

1. Daily massaging of sesame seed oil on the skin and then taking a bath after half an hour.
2. Making a mala of Tulasi beads which are  held together by a copper wire should be worn all day.
3. Wearing a Copper bracelet
4. Eating Trifala with warm water in the nights.(Pregnant ladies,weak and sick people should avoid taking Trifala)
5. Taking around 20 gm of aloe vera gel in the evenings with  pinch of sugar.         

All this definitely minimize the effects of unwanted radiation to a great extent.