anchor.diff:  
   /obj/machinery/portable_atmospherics/canister/Initialize(mapload, datum/gas_mixture/existing_mixture)
   	. = ..()
  +
   	if(existing_mixture)
   		air_contents.copy_from(existing_mixture)
   	else
   		create_gas()
  +
  +	var/random_quality = rand()
  +	pressure_limit = initial(pressure_limit) * (1 + 0.2 * random_quality)
  +
   	update_appearance()
   
   /obj/machinery/portable_atmospherics/canister/ComponentInitialize()
  
positive.code: /obj/machinery/portable_atmospherics/canister/examine(user)
  	. = ..()
  	if(mode)
  		. += "<span class='notice'>This canister is Tier [mode]. A sticker on its side says <b>MAX PRESSURE: [siunit_pressure(pressure_limit, 0)]</b>.</span>"
  
  /obj/machinery/portable_atmospherics/canister/nitrogen
  	name = "Nitrogen canister"
  
negative.code: 
  /obj/machinery/portable_atmospherics/canister/tier_3
  	heat_limit = 1e12
  	pressure_limit = 9.2e13
  	volume = 5000
  	max_integrity = 500
  	can_max_release_pressure = (ONE_ATMOSPHERE * 30)
  