plastic retaining wall, plastic piling - KLP - Lankhorst Recycling ..For the finishing touch we supply KLP? plastic fenders. Combined with KLP? Prowal we offer KLP? Combi-posts and reinforced KLP? Poles for fixing of the partition. With KLP? you can opt for a sustainable solution! plastic retaining wall systems. The KLP? Combi-post consists of an untreated timber pole that is moulded.