Spacer with metallic side sections

A spacer for insulating glass units, comprising:

• a U-shaped main body extending in a longitudinal direction including a first metallic side section, a second metallic side section arranged parallel thereto, a polymeric connecting piece extending in a transverse direction, which connects the first and second metallic side sections and forms a lower limit of the main body, and an intermediate space arranged above the polymeric connecting piece between the first and second metallic side sections, wherein
• the first and second metallic side sections each include at least one side wall for connecting to a glass pane and a retaining arm, which protrudes into the intermediate space, and the retaining arm forms an assembly groove with the side wall, which groove runs substantially parallel to the side wall,
• the polymeric connecting piece is U-shaped and includes two legs that are inserted into the assembly grooves of the first and second metallic side sections.