These Strain Gages are designed for direct embedment in concrete. The 4200 (standard model) has a 153 mm gage length and 1 με sensitivity and is commonly used for strain measurements in foundations, piles, bridges, dams, tunnel linings, etc. The 4210 has a 250 mm gage length making it particularly suitable for use in large aggregate concrete. The 4202 is designed for laboratory use and/or where there are space limitations. Low modulus versions, for measuring concrete curing strains, are also available (please contact us for details).