As per this deal, you can choose one of four vouchers when you perform a balance enquiry or make a withdrawal at a Coles Express ATM.
ING Direct will refund your ATM fees if you have had $1,000+ transferred into your account in the previous month.
Coles MasterCard won't charge for a balance enquiry at Coles Express.
Otherwise it's $1 for balance enquiry / $2.50 withdrawal.
Assuming voucher availability is like that of previous deals, the voucher will remain selectable until April 8 and redeemable until April 22.
Further to my comment above. As of 4pm today Asburton is out of stock.