<ARTICLE> 5
<RESTATED> 
<MULTIPLIER> 1000
       
                                                                                            
<PERIOD-TYPE>                   3-MOS                   6-MOS                   9-MOS                   YEAR
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1997             DEC-31-1997             DEC-31-1997
<PERIOD-END>                               MAR-31-1997             JUN-30-1997             SEP-30-1997             DEC-31-1997
<CASH>                                           5,350                   2,560                   2,321                   4,300
<SECURITIES>                                         0                       0                       0                       0
<RECEIVABLES>                                   49,860                  52,903                  55,827                  58,431
<ALLOWANCES>                                         0                       0                       0                       0
<INVENTORY>                                     19,995                  22,849                  22,476                  22,324
<CURRENT-ASSETS>                                77,303                  80,410                  82,722                  87,752
<PP&E>                                          81,541                  77,356                  79,314                  76,766
<DEPRECIATION>                                  50,492                  45,586                  47,012                  44,179
<TOTAL-ASSETS>                                 133,363                 136,942                 140,022                 143,654
<CURRENT-LIABILITIES>                           28,027                  26,715                  29,211                  29,196
<BONDS>                                         15,160                  18,540                  17,001                  17,160
<PREFERRED-MANDATORY>                                0                       0                       0                       0
<PREFERRED>                                          0                       0                       0                       0
<COMMON>                                        33,504                  33,707                  34,086                  35,350
<OTHER-SE>                                      54,545                  55,853                  57,597                  59,870
<TOTAL-LIABILITY-AND-EQUITY>                   133,363                 136,942                 140,022                 143,654
<SALES>                                         39,631                  80,677                 122,983                 171,230
<TOTAL-REVENUES>                                39,631                  80,677                 122,983                 171,230
<CGS>                                           26,035                  52,745                  80,731                 111,925
<TOTAL-COSTS>                                   26,035                  52,745                  80,731                 111,925
<OTHER-EXPENSES>                                10,985                  22,199                  32,691                  44,892
<LOSS-PROVISION>                                     0                       0                       0                       0
<INTEREST-EXPENSE>                                 395                     791                   1,297                   1,849
<INCOME-PRETAX>                                  2,132                   5,041                   8,300                  12,315
<INCOME-TAX>                                       829                   1,992                   3,299                   4,924
<INCOME-CONTINUING>                              1,303                   3,049                   5,001                   7,391
<DISCONTINUED>                                       0                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
<CHANGES>                                            0                       0                       0                       0
<NET-INCOME>                                     1,303                   3,049                   5,001                   7,391
<EPS-PRIMARY>                                      .15                     .36                     .59                     .87
<EPS-DILUTED>                                      .15                     .35                     .57                     .84