@Override public int increment(ItemStack stack,int amt){
  NBTTagCompound nbt;
  if (stack.hasTagCompound()) {
    nbt=stack.getTagCompound();
  }
 else {
    nbt=new NBTTagCompound();
  }
  int prevAmt=nbt.getInteger("air");
  int newAmt=Math.min(prevAmt + amt,getMaxAir());
  nbt.setInteger("air",newAmt);
  stack.setTagCompound(nbt);
  return newAmt - prevAmt;
}

@ Override public int increment ( ItemStack stack , int amt ) { NBTTagCompound nbt ; if ( stack . hasTagCompound ( ) ) { nbt = stack . getTagCompound ( ) ; } else { nbt = new NBTTagCompound ( ) ; } int prevAmt = nbt . getInteger ( "air" ) ; int newAmt = Math . min ( prevAmt + amt , getMaxAir ( ) ) ; nbt . setInteger ( "air" , newAmt ) ; stack . setTagCompound ( nbt ) ; return newAmt - prevAmt ; }
increments air in the suit by amt
