In addition to merchandize you will find in most convenience stores, the store provides laundry, photo developing/printing, parcel delivery services.  
They handle bus ticket from Tsukuba Center to Narita Airport including taking a reservation for it. 
They also handle sets of bus tickets inside Tsukuba.
Location : 
      Between the Shokuin-Kaikanbldg. and the International 
        Center (Ext. 3907)
Hours : 
      Monday-Friday   9:00-19:00 
   
      Closed on National holidays, Year-end / New-year holiday and KEK
     
  set holiday.