3M(TM) Urethane Foam Tape 4104 Natural, 2 in x 18 yd 64.0 mil, 6 per case 3M(TM) Urethane Foam Tape 4104 white, 6.4mm thick, High density open cell foam, acrylic adhesive one side 3M(TM) Urethane Foam Tape 4314, acrylic adhesive is protected by a tan, silicone treated paper liner. Very soft, conformable, low density foam which can help seal out air, dust and light when compressed 50 percent.