Do u beleive in 'Tabeez'?

If ur language is Bengali,Urdu or hindi ,u know what a tabeez is.But if u r from any other contry i donno what u call it in ur language.A tabeez is a special kinda locket inside which Quranic Ayahs r written in papers in symbolic manner and then enclosed within it .Some people who r called 'PIR' gives tabeez to people.Many people wear them around neck,arms, or waist as suggested by the pir with various desires in mind such as-well being from disease,good result in exams,profit in bussiness,Finding a good life partner etc.And it is often beleived that tabeez can b used to harm or even kill people.What i really wanna know is do u tabeez has the power to effect people both positively and negatively?