no longer giving samples...or that's what they replied to my request. Min order is $10, grommets are $1/ea & $2 US shipping (may be more for larger orders, they didn't say)....so my free tank building hopes are on hold. when I have $12 to spare I may go for it. would like to know if any one decided if it was the -04 or -21 tubes that these fit plz?