A male touch fastener strip (100,100',100",100"',200,300,400,500) comprising: an elongated base (102,202,302,402,502) having a thickness and defining a longitudinal direction and a lateral direction perpendicular to the longitudinal direction across the base between longitudinal edges of the base; a field of male fastener elements (110,210,310,410,510,510a) each having a stem extending from a broad face of the base and a head at an upper end of the stem and overhanging the base for engaging fibers, the fastener element stems and broad face of the base together forming a unitary mass of resin; longitudinal barrier walls (104,204,304,404,504,604) rising from the broad face of the base on either side of the field of male fastener elements; a pair of segmented walls (106,106',206,306,406,506) rising from the broad face of the base, each segmented wall of the pair disposed laterally outboard of a respective nearest one of the longitudinal barrier walls, each segmented wall comprising a series of wall segments (118,118',418) defining longitudinal gaps (120,120',220,420) there between; wherein each segmented wall (106,106',206,306,406,506) is configured to cooperate with a nearest barrier wall (104,204,304,404,504,604), with the male touch fastener strip supported at least by the barrier wall against a mold surface, to permit a limited amount of foam to intrude into a respective foam relief space (122,222,322) defined between the cooperating walls, characterised in that each segmented wall (106,106',206,306,406,506) defines a flow gap for allowing the foam material to enter the respective foam relief space (122,222,322), each respective flow gap having an area per unit strip length; and wherein the ratio of foam relief space volume per unit strip length and flow gap area per unit strip length is between about 0.05 and 2.03 cm [0.02 and 0.80 inch],preferably, between 0.76 and 1.14 cm [0.03 and 0.45 inch]. an elongated base (102,202,302,402,502) having a thickness and defining a longitudinal direction and a lateral direction perpendicular to the longitudinal direction across the base between longitudinal edges of the base; a field of male fastener elements (110,210,310,410,510,510a) each having a stem extending from a broad face of the base and a head at an upper end of the stem and overhanging the base for engaging fibers, the fastener element stems and broad face of the base together forming a unitary mass of resin; longitudinal barrier walls (104,204,304,404,504,604) rising from the broad face of the base on either side of the field of male fastener elements; a pair of segmented walls (106,106',206,306,406,506) rising from the broad face of the base, each segmented wall of the pair disposed laterally outboard of a respective nearest one of the longitudinal barrier walls, each segmented wall comprising a series of wall segments (118,118',418) defining longitudinal gaps (120,120',220,420) there between; wherein each segmented wall (106,106',206,306,406,506) is configured to cooperate with a nearest barrier wall (104,204,304,404,504,604), with the male touch fastener strip supported at least by the barrier wall against a mold surface, to permit a limited amount of foam to intrude into a respective foam relief space (122,222,322) defined between the cooperating walls,