I came across this article on Bhaji Daljeet Singh's blog. It is very informative and helps explain the significance of the Hazooria (white material put around the neck). Daas wear's a Hazooria, especially when going to the Gurdwara, however a lot of times people have asked me "Why are you wearing that?"Sometimes people say "Erm... isn't that for Gyani's?" Also when doing sewa in the Gurdwara for example reading Gurbani or doing Chaur Sahib di sewa one has to wear a Hazooria, but some people don't know why we do this. The article below helps to explain the significance of the Hazooria:
Article from Bhaji Daljeet Singh's blog:
Hazooria; hazoor: Being ready; being in presence.
There have been many mahapurkh (spiritual elevated persons) who have worn a hazooria, most of us don't know the real significance of the hazooria, and why we should wear it.
5 Kakaars are the bare minimum and are not the full extent of Khalsa uniform. A hazooria is part of Khalsa uniform. It can be white or blue and past the waist in length. In Mehta Chownk (a Sikh education centre renowned for teaching how to read and understand Gurbani), all singhs have to have a hazooria to enter mahaaraaj's hazoori (Guru jee's presence).
It is part of the tradition of panj kapare (five garments), comprising dastaar (turban), hazooria, long chola (dress), kamar-kasaa (material tied around the waist like a belt) and kachheraa (under-garment). Reference to this has been made by Bhai Gurdaas Jee as well.
A hazooria is a sign of humility and that's why when doing ardaas it's grasped. It is a constant reminder of surrendering your mind to your Guru, along with your punj kakaar. A Hazooria is very practicle. It helps you keep succhamta (cleanliness) when during seva or reading bani. If you want to keep your hands clean when scratching face or picking up something, you can use your hazooria.
Hazooria is usually worn by servants as they serve their master. For Sikhs, it similarly symbolizes servitude to the One and Only One True Master - Akaal Purakh and Sri Guru Granth Sahib Ji.
While the kamar-kassaa (material tied around waist like a belt) symbolizes the readiness of a Sikh to do some active seva, or jump into battle the Hazooria is mark of a Sikh's readiness to serve Guruji.