well what i have heard about this new shield grenade, also known as the bubble bomb is used to withstand a massive blow, as seen in the commercial it withstood a wraiths blast, so in terms i believe these grenades will not be at all rare, or very common i believe it will be just like any other grenade, but little less than the common grenades. Many uses for this grenade may be used to with stand a scarab gun blast if one is present, withstand massive suppressive fire from the enemy, and protect yourself from incoming grenades.